“Am I positive from covid from previous infection or do I have covid again?”

I'm not sure if you would be able to answer this, but I had covid at the end of December but started testing negative around December 27th. Now I'm experiencing symptoms and testing positive again. Could this be a different illness and the test is picking up a dead covid virus? Or since I tested negative after the initial infection would this actually be covid again?

I am testing positive with at home and PCR tests.