Lack of interest in sex

Courtney • Vegan. Animal Rights Activist. I love cats. I run a fitness website (cupcakestoproteinshakes.com) 😁
I have a lot of issues, one of them being diagnosed as having severe anxiety, and moderate insomnia and depression. I'm planning a wedding, waiting to be discharged from the military, just had heart surgery 2 months ago, and I'm über stressed out. Anyway, sex always is the last thing on my mind and I wasn't always like that. 
My fiancé is very loving and supportive, but I feel bad because it's 100% me that's not interested in the activity, it's not him. I'm very attracted to him, but in my mind I feel like it's just something else I have to get done for the day and I feel horrible about it because I love him so much.
Before anyone replies suggesting I am not attracted to him, I'm telling you that Magic Mike could walk in here and offer it to me, I still would feel the same way lmao it's 100% mental with me. Is there anyone out there that's experienced this before? And how did you cope? I also want to add that I am on medications for my insomnia and anxiety.