holding back tears during sex

Daisy
I'm lost and just wanted some advice or someone to talk to. I've been married for 8 months (virgins when we got married) and I've had a very up and down sex life. We don't have sex often, sometimes it's great and I feel sexy and awesome afterwards, or sometimes (tonight) I get very very emotional. It starts off with me not really wanting to have sex but feeling bad if I say no (cos we rarely have sex) so I close my eyes, grit my teeth and pray for it to be over. Afterwards and sometimes during, I find myself trying not to cry. I just get really upset and not sure why. Has this happened to anyone else? X