Positive then negative pregnancy tests

I’m so confused. I’ve had spotting the last 4 days and that’s abnormal for me. I’m not expecting my period for another 5 days. Yesterday I took a pregnancy test (equate brand) and got a faint positive. It was very faint, but it was still there. I just took one this morning (clear blue) and it was negative. Yesterday my boobs hurt like crazy too so I was like well I’m for sure pregnant. With my first pregnancy, I was getting positive tests around this time. Has anyone been through this?! I’ll obviously keep testing but this is so frustrating.