faint positive

A❤️C

so on Friday after not starting my period for 3 days I took a test I got the faintest positive that could barely see. so afterwards I took 2 more tests. both were negative. then I basically started my period 3 days later its starting to end already. any opinions? I'm feeling confused. maybe chemical pregnancy? I also had back pain and cramps for 3 days with nausea