I just wanna give on everything all together

I don’t understand. My partner is hanging and spending the night at his friend’s house doing eventual full things with them. We usually are at home relaxing and being together and sometimes in silence doing our own thing. We don’t go on dates often.. b/c last time when we did go on a date I had very bad intrusive thoughts about not loving him… But after him telling me everything he did today. I started to question everything all over again and wanted to cry… I have been obsessing if we have enough in common.. I want to do more things together but with the constant break up thoughts and constantly thinking I don’t love him…. Doesn’t help… I am starting to question everything more and I haven’t felt anything for awhile now…. We had sex last night too… I felt nothing… I couldn’t get turned on like I usually do.. I am on 100mgs of Zoloft…. So I wonder if that is the case… I get so depressed I can’t function…. It doesn’t help that… my cat my fatty baby girl most likely is dying from mouth cancer… she hasn’t been acting herself.. seeing her throw up and having the runs badly is causing me to break down more… Life I know can be unfair.. but with everything bad happening… how can I have faith… how can I be better or get to be happy with everything bad happening… she also has a vet appointment this week… I’m scared that I have to put her down… 😢 I know I went off track… sorry.. I have been self conscious about my weight.. my partner said he loves me no matter what size I am but.. I am disgusted with how I look… I wanna lose weight but been using food as comfort. I know that I am not happy anymore.. the relationship isn’t the cause it’s everything else that is…. How can I strengthen my relationship when I constantly believe I don’t love him anymore…