OK unlike some of the previous post, I'm gonna try and attempt to answer the OP's post with some positive knowledge from my own perspective.
Firstly like the OP has mentioned about him/herself, I too am a regular flyer, doing about 4-5 flights a month for work. I also was a very nervous flyer to the point that I did not fly for 5 years and avoided going overseas because of it.
I now fly all over the world, on my own and without the anxiety I used to carry on board with me. I never thought I would get to this point but I have and I thought I would share it with you on how I dealt with it.
Firstly, I would just like to comment on some of the previous comments made, these are just my opinions.
"I highly recommend you buy bach rescue remedy"
This might be of some benefit but like the poster mentioned it might just have a placebo affect. Nothing wrong with that, placebos are very powerful but I do feel the OP needs to understand and change their perspective on what turbulence is and the risks involved.
[i]The only other thing I can suggest is trying to sit opposite a jump seat occasionally and have the crew chat to you about what is happening[i]
This can be very helpful, but mainly for people not so aware of their surroundings. The OP mentioned that they fly very often so familiarity is something they possess. However, maybe the OP has 'avoided' getting familiar so this may be of some benefit for sure.
There is that BOAC 707 that was ripped apart in Japan by turbulence.
It never surprises me when you talk to some people (like I used to) about a legitamate fear or flying you end up with a totally unhelpful and fear-riden response that adds nothing but useless sound bytes.
As for Boeing G tolerances, there is that China Airlines 747SP that fell off the sky (It had rolled over). The black box was broken by the acceleration, so the g-s achieved were over 5g, but exact numbers are unknown. The wings were permanently bent - slightly, and they remained within tolerances. Parts of tailplane broke off. Out of over 270 people aboard, one had a leg injury and another had back injury. Everyone else was unscathed.
This is just rubbish and nothing to do with turbulence which is what the OP's question(s) were related to. The cause was never 100% confirmed but the Captain had problems with no. 4 engine before the plane encountered any problems. Again, I don't believe any of this was helpful to the OP's original post.
There have been people killed by turbulence in airframes that kept flying.
Yeah and there's probably someone who's been killed painting their nails. It's very very rare for someone to be killed by due to turbulenece. In 'severe' CAT, which in itself is very rare to encounter (ask a pilot) there have been injurys to people not belted up and to CC, that's why you wear a seat belt.
OK so now onto how I dealt with flying in particular turbulence. The first thing to do is look at air as fluid. Just because we cant see it it's actually quite a thick substance when travelling at speed. If you put your hand out of a car window at 50mph you'll realise that it's very similar to wading through water. Now imagine that at 500mph, the air is very very thick like Jelly (Jello to our American friends). Now imagine a big jelly on a plate and shove a miniature model plane in the middle if the jelly so it is suspended both vertically and horiztonally. That's in simplistic terms is what the plane is, in thick jelly, suspended in the air because of the density of it. Now if you start feeling turbulence, this is simliar to wobling the jelly or pressing down on the top of the jelly. The air is still thick and you are still stuck in it's treacle like density but the path of the air has changed and therefore go up, down, side to side. Even those sudden jolts of falling is generally just very minor altitude shifts (look at the video display and see if you have fallen or climbed significantly, the chances are the read out is negligable). This applies ot severe turbulence but the path the plane is taking is naturally more excentuated, however the air is still thick. Now if you are a fearful flyer, you;re only intereste in those reports you hear about CAT and a plane dropping thousands of feet. OK these happen and by all accounts any prolonged turbulence or sudden jolts are not pleasant for anyone, but the planes CAN handle it. The wings will not snap off, the plane will not barrel roll and you will not die from it.
The whole way of dealing with this is to comprehend that doing 'anything' carries a risk BUT really understanding and comprehending the risk is extremely minimal, especially when it comes to being a pax on a commercial aircraft. Turbulence carries hardly any risk at all, not pleasant I agree but risky no. The pilot wont be enjoying it either and will be aware that it is uncomfortable for his/her passengers and in turn will comminucate with other aircraft to see if there is any smooth airspace around as an alternative, but they wont be feeling like you do at the back of the bus because the comprehend fully the risk involved and know it to be negligable. I remember when I was coming back from JFK to LON on BA. I was in the upper deck and it was qiote bumpy, I was aware of this and not really enjoying this, when I noticed the Captain come out the cockpit, have a joke with a CC, go to the loo and hang around the galley for a while just shooting the breeze (no he wasn't briefing the CC for an emergency, which is what my IMAGINATON was telling me).
Anyway, I have gone on far too long. If you want to PM me I will tell you a very very helpful course for aux fais flyers. It takes about 6 weeks (watching DVD's) but was extremely helpful for me. I didn't post the details here because I didn;t want anyone to think I was part of the company (which I am not).
Good luck in overcoming your fear