Levoxyl and adipex

I've been on levothyroxine 150mcg for about 3 months before that it was 100mcg and so on. I have gain lots of weight and tired all the time. depression also, headaches. I hate this gaining weight, sleepy all the time and depression is from gaining weight. I thought this med is to up boost my thryiode but it doesn't seem to be working. my dr. said I'm on the highest dose there is. I don't know what to do any more. I was thinking about taking myself off this but not sure what will happen if i do. I hope there is someone out there that might be able to let me know if they are going through the same things what they are doing and how they feel now.