I need help. I've taken 4 test. 2 of which were the ones that tell you sooner and they were…

I need help. I've taken 4 test. 2 of which were the ones that tell you sooner and they were positive. The other 2 were from the dollar tree and tell you day of missed period and those were negative. I don't know when my period is because I had an iud and had it taken out so everything has been off. Any suggestions?