Should I be worried?

When my boyfriend and I have sex we're always protected and make sure the condom didn't break but lately I've been feeling bloated and have nausea but i never actually puke. The nausea could be because I have asthma and sometimes it's hard to breathe making me feel nauseous but that doesn't explain the bloated feeling. My stomach also feels tight. His penis has been around my vagina before and after but I'm not so sure if there was any cum on it. I feel like I might be lactose and lately I've been having a lot of dairy so it could be that but I worry easily and feel like i could be pregnant. What should I do? ( I get my period around the last week of every month and i got it in September)