False positives

Within 4 months, I've had two positive pregnancy test. But then I would start my period later or on time. I just don't understand why my body gives false positives. The last time I had one, told my husband. He was beyond excited that it was positive. Then had me take more, negative. I didn't tell him about yesterday's positive. Took another test this morning. Negative. My boobs hurt, I'm cramping. I'm nauseas. Thankfully I stopped spotting. (Five days after my period ended) my mom thinks maybe it was a miscarriage because of how bad this period was. I don't know. I'm getting real tired of these false positives, it's making me upset. Sorry just really having to vent alittle.