Paranoid?

So my boyfriend and I have been dating for nearly six months and we were both virgins when we had sex with each other. We have done it plenty of times. I feel like even though we use protection, we are always afraid and paranoid that I may be pregnant. Even though I know that I'm not. So last week I took two pregnancy tests and they both came back negative and then the next day I started my period and it was some what normal. I'm still just kind of paranoid because I've been dizzy lately and tired and I am really bloated and I just feel off. What could it be?