help!!

Lately I haven't be wanting to have sex. last night me and my husband was having sex and I started crying. he asked me what's wrong and I told him I don't really want to have sex with him since I been pregnant. i think it's because this is my first pregnancy and I have a very high risk ( heart problems). I'm just scared something will happen to the baby. should I be worried having sex. I feel like when I get to 2 trimester I don't think ill have a problem with having sex with him. What shpould I do? does other people feel like I do