I started taking Doxy for acne. I took 100 mg 3x a day. My stomac...

I started taking Doxy for acne. I took 100 mg 3x a day. My stomach is a bit upset every now and then but nothing I can't live with. My acne cleared up pretty quickly. I noticed my teeth are alot less white than before, sort of turning brownish tint. But what I really noticed is how tired and lethargic I have become. I've become very depressed and my self-esteem has dropped. I've always had somewhat of an issue with this but now I don't even feel like getting out of bed. I have to force myself to go to school, belly dancing classes, and work. My partner complains my sex drive is so low. THis could be from the depression. I don't want my acne to come back but I can't go on feeling this way.