I am stuck in a rut, can you help?

I was on steroids for a brain injury from 2001-2002, and placed on many meds after until 2006. I have been dieting and working out since 2008. I lost a ton of weight and gained a lot of muscle, for about a year and a half.

Its not that I am weak now, havent stopped going to the gym either, and I havent changed good food habits lately that much either. I started grad school in November, and I feel like I am sitting too much even though it isnt for very long ever at any one time. I feel swollen and bloated although all of my clothes fit better and I dont look fat, I just feel morose.

Is there a reason for this? Is it just because I feel cooped up? I am still new to the whole healthy lifestyle, so please let me know if this is just a mental feeling or if I probably am retaining water after New Years/ Christmas/ Birthdays?

Please dont sell me on any pills either. Thank you