To be slightly less harsh on the OP.
After my first year in aviation I had been hired, made redundant, hired again, and then suffered another 6 months of job security issues. The flying was monotonous, with very little opportunity to seek challenges or learn, and every day was spent with guys who were exceptionally stressed about losing their homes, having to explain to the wife that there wasn't going to be a paycheck anymore.
At the end of that year, I was also going through the same thought processes. I wasn't being overly challenged, I wasn't enjoying the stressful environment created by my employer, and seriously considered if this was the right career for me.
After about 2 years of flying, I managed to get on with my current employer, a large flag carrier. I am well treated, well paid, and have a lot of free time. I fly to a variety of interesting destinations and have time off down route. I often now have to pinch myself and be reminded I am being paid. I also consistently bid for, and swap on to the trips others don't want due to the perceived challenging nature of the destination, the best days out are the ones that make me think and give me some experience. I find it deeply rewarding to "feel" myself becoming more experienced, and better able to anticipate things.
It just takes a realisation that if you want the freedom of flight, to point anywhere in the sky you want, you need to go rent an airplane. The airlines are a job, a very enjoyable job, but a job nonetheless. You also need to seek the sanity of non LOCO flying if you are joining young and want a career, the LOCOs just want to slog your guts out for a few years and spit you out the other end.
Also, don't get in to the habit of going straight to bed down route, even if the crew aren't up for doing anything, go out on your own and explore. A Captain told me, "the default answer to anything should be yes".
The feeling passes. I honestly believe it is because you have just spent the last 21 years chasing and running toward this dream, you have achieved it, and now what? It's just a change of psyche.
Best of luck!