Bed bugs.

When was about 15 weeks I was getting bit by something but wasn’t sure what it could be.... someone suggested bed bugs but I was in denial and said no way, we are way to clean!! Low and behold we found a couple. So we cleaned everything and got rid of our bed and bombed and did everything!! We were good for awhile and recently the last couple weeks I’ve noticed bites again and my husband kept checking and couldn’t find anything. One day I said you need to check harder something is going on and it hurts!!! He went up and checked and found the tiniest little bug. Literally the only one we found. We have a bed bug cover on our mattress and then a regular mattress cover also. Took apart everything and found nothing. So we washed everything again and sprayed and bombed last weekend and seemed like everything was ok. Last night I woke up and my arm was eaten up! (They only bite one part of my body and don’t bite my husband or my daughter I’m 36 weeks pregnant also) I need help and opinions. We can’t afford an actual exterminator we’ve tried fitting it into the budget and we just can’t do it. We just keep checking and can’t find anything so I don’t think we are infested, I just don’t know anymore ☹️