Confused?

me and my boyftiend have been trying for over a year to conceive. we already know it's hard on his end but we know it's possible. on the 21st of August I took a pregnancy test and it came out positive. so excited but I wanted to confirm before I told him. I took another and it was negative. I didn't get upset just figured I'd take one more the next morning. but that one came back negative too. fast forward to mow and I just got off my period Sunday. but it started on Saturday so it was one day and light for me. I haven't been feeling good all weekend, tired, headache, not that hungry. anyone have any insight?