Advice needed🚫

So I am curious as to know everyone’s responses. My monthly hasn’t been on since June, and my boyfriend and I had sex June 14. I feel as if I’m not pregnant because I also took a test a few days after we did it and that came back negative. I know it was took soon to take the test but I took another one this pass Monday and it came back negative too. My breast were hurting me really bad a couple days ago and they feel heavier now. Sometimes I do have lower belly pain, nauseous to where my mouth waters and back pain but I figured my monthly is about to start or I’m just hungry but still nothing. I just don’t know what else it could be. Should I take another test? Or am I just stressed and my body is playing tricks on me. I am really worried though that something is wrong with me. I don’t really have anyone else to talk to so I turn to the community.