late period and non-existent sex drive.

Audrey
So I have a slew of medical issues going on, and because of that I constantly have cramps on my left side. This last cycle, my period was 12 days late. I took pregnancy test after test and they call came up negative. 
Also through all this I have had zero desire to have sex with my boyfriend. It's not that I didn't find him attractive, I'm just never in the mood anymore. This is really abnormal for me, normally I couldn't jump on him anywhere. 
Anyone experienced anything like this before? I can slowly feel it affecting my relationship 🙁