All my test come back positive but doctors don’t?

I had an appointment on Monday and had a positive test from the Thursday before up to Saturday. ( Sunday I didn’t test) but all their test is coming back negative and than this morning started bleeding.. I don’t understand. This has happen multiple times. Once even with a digital and than I’m getting told oh you’re read the test wrong and that I’m obese that’s why my periods late. But yet I’m getting positives.. so annoying