Ok - this is what should happen:
You're still in a way recovering. It takes a loooong time.
Find out your tsh and if taken t4, t3. Tsh is most reliable measure at this stage.
See if there's any wiggle room on it. If your tsh is say 2 or 1.5 (or above) you could potentially take two extra 25s a week. If your tsh is 0.8 that's pretty bang on. Lowest is usually 0.3. Ask your gp to help you safely maximise this.
You don't actually put in a great deal of weight when hypothyroid, you can 'put on' some water through water retention. (Sorry but true). What does happen though is that hypothyroid people do get tired and loose muscle strength and so, if calories in exceeds calories out you'll put on weight.
Find out how your ferritin, vit d and b12 is and if not good, try to get those levels in their upper ranges to improve energy. Ferritin should be over 70.
I would follow the diet and exercise advice of anyone else once these things are good. You may need to pace more than the average person. I have found when I get physically strong (through yoga) and do cardio i am generally much much healthier, have more energy which will lead to weight loss. Counting calories, although annoying, does help. More protein helps you feel fuller for longer etc.
But start with the levels.
A very few people need extra t3 or just t3 but this is done after eliminating all other issues. T4 is the safest and when I keep in top of all these things I've been healthier and fitter than some friends without needing extra t3.