It sounds like everything is going well for you, and that you will get on top of this.
My impression of those early hours was of each lesson being about revision of the last lessons, then just as you master some of the early lessons here is some more to learn!! So you do always come away feeling that you will never cope and it is not going well but it is the best way to learn in an economic manner - if you were just flying around perfectly straight and level for hours you would feel that you were wasting your time, rather than head exploding from too much!
I would say that you should start doing the RT, the insdtructor is of course there to take over if there is a problem. But, there is an easy way - get some plastic A4 "pockets", like plastic sleeves. Type up on the PC a sheet of A4 with the text of the ATIS but leave gaps for the tings that change like runway in use and QNH etc. Do the same fruther down the page for lists of the regular calls that you need to make, leaving gaps for things like "Reg", QNH, and the message for the tower/approach. Slip this sheet into the sleeve/pocket, and put this on your kneeboard.
Buy a set of fine pointed permanent markers like you would use on your map, you can always clean the writing off after with meths on a tissue.
Then, first thing you do once seated in the plane is listen to the ATIS, do this for as many times as YOU need to get EVERY detail written down. If the instructor listens to it once then turns it off, say you need to hear it again, and again so that you have then written down all the salient points. You will then know the QNH, wind, runway in use etc and also what frequency to call for your first call to the tower or approach (Hint - dont write T O W E R, have Tower/Approach typed out, and just circle the appropriate one)
So you now have all the information to make the first call to the tower - just read it out. Dont feel silly if your version 1 of this crib sheet has every smallest call detailed - it will help you to remember it much more quickly. The same is true for the rejoin, and landing instructions, except you have to be a bit smarter about writing the details down, propbably quite abbreviated. To be fair on rejoin, all you need is the QFE, runway in use and the number you are in the circuit.
I did this, and was surprised to see copies of this being used by quite a few other student pilots !!! (PM me if you want a copy of what I used)
One last thing before this post is as long as a Thom book, do not be afraid to take a lesson or two with different instructors. If you need to be cunning and call up to make a booking when your regular guy is off, do it. Its not sneaky, just say that is the only day you can make that week. You will so be surprised what a difference this will make to you - some things that you thought you were doing well will be slammed by the new guy but (s)he will really help you out here, and others you thought you were rubbish at will be a breeze. Treat it as a learning experience. Boy will you learn, especially in the early hours, as this is where all the basic stuff is being drummed into you so you can get onto the interesting stuff!