Miscarriage or period?

I had a positive pregnancy test, but then two negatives right after. The positive was from a good brand, the second was from a good brand and the third was from a cheap brand.

My period was due on the first of July, and I tested on the third.

5th of July I had sharp stings in my abdomen, very different to period cramps. I put a pad just in case and went to sleep, when I woke up, the pad had almost black blood, quite a bit, really. Hours later I began bleeding to the point where I needed to change it every hour or two (I could get away with changing it every four hours because I bled so little) I still have moments where I feel a stab, so unfamiliar.

My sister was pregnant and got her period so I didn't think anything of it.

I have quite a few blood clots and I've never had them.

I know I should see a professional but my gyno isn't available until next week.