I can't get horny :( + other stuff

Rain
So lately, ever since my last period, I've been sleeping and sleeping but I'm always tired and have no energy whatsoever. 
Worse, i don't get turned on anymore. 
It's been like 3+ weeks and I just don't ever feel horny. I've been really badly constipated too though. 
Every time I try to have sex I just don't enjoy it. I still get wet, that's not the problem. It's as if the part of my brain that gives me pleasure is off. I've been really depressed too but I've been very depressed for a while and this month is the first time I had this issues. 
I went to the doctor and they didn't find anything medically wrong. 
I just don't know what to think  anymore or how to fix it.