New training, new diet, new start — colitis week 1

Alright everyone, here's the situation... I was diagnosed with colitis about six years ago and didn't take meds until a flare last year. At the moment I'm on 1600 mg Asacol daily and 5 mg pred every day supposedly for life... I stopped the pred because the side effects were brutal, but the condition seems under control without it. Over the past five years I've tried every diet and training plan you can think of and I've always been between 92–102 kg whether I'm using gear or not. At 191 cm and fairly lean that weight just isn't enough. I've followed every tip from people at the gym — eating massive calories, high reps, low reps, drop sets, clean eating, junk food, mass gainers, and every kind of steroid — and still the scale won't budge past 102 kg. Training for five years and getting a fraction of the gains others have (even someone who trains half the time) has really knocked me back and depressed me. Some of my symptoms: fatigued, lethargic, anxiety, feeling drained, no weight gain, depressed, very small lean muscles that don’t feel strong — basically feeling awful. My current split is: Monday chest, Tuesday back, Wednesday legs, Thursday off, Friday shoulders, Saturday arms, Sunday off. Usually 4–5 exercises per bodypart and 4 sets of 8–12 reps. Saw my doctor just over a week ago, told him everything and he referred me to a colitis nutritionist... then I told him…