Bad thoughts or bad sex?

My fiance and I have been together for a year and a half now. when we first got together we were having the most amazing mind blowing sex multiple times a day 😍. This went on for about 8 months. The sex kind of slowed down a little bit (which we both expected.) Last year, July 2017, we ended up moving to Kentucky for work. He ended up working really long work days. Sometimes i wouldn't see him for almost two days. He worked for auction in the auto body shop. We started fighting.. a lot. He was convinced I was going to leave him, ( rough past with ex's) and started comparing me to his ex's. We constantly fought, almost every day. We would go 2 weeks without sex sometimes. I would turn toys as a relieve. Fast forward a couple months, we decided to move back to our home state, Virginia. Well we are currently living with my father and brother in law. Not so much a big deal. We have our privacy and we don't get bothered that much. When we moved back, we knew it would be difficult trying to get used to living with family. We have been living here for the past 4 months. We have had some pretty good sex, but nothing like what we were having before we moved to Kentucky. For the past month or so every time we have sex, I cant keep myself focused enough to get off. I keep telling myself that I'm not good enough for him anymore, I'm to fat for him and he's not enjoying the sex anymore.(I have gained a little bit of weight with all the stress of moving twice.) He always tells me he loves me for who I am, and I'm not fat in his eyes. He reassures me that he enjoys being with me and doesn't worry about anything else. I have actually broken down and cried during sex, only because I actually start believing these thoughts. We haven't had sex in almost a week. I've tried talking to him about how I feel the sex isn't good enough anymore and he brushes it off and tells me its still great sex and I am just over thinking. Which I may be over thinking it but these thoughts and feelings have been going on for almost 6 months...