Is there any way i could still be pregnant😥

I had a pos test about a week and a half ago, followed by a negative. Bled, passed clots, tissue, etc. Chemical right? I still have minor aches and nausea and i still feel pregnant. Is there any way I still could be pregnant? I plan on testing today at some point. But im not sure if thatll just be a waste of $$.. 😐