Is this a Miscarriage?

So I started bleeding bright red blood with black small clots. Thought it was a period. But a few hours after the bleeding started I got very painful pressure in my vagina, and it's not going away. Craps are very mild, but walking, sitting, or moving too much hurts so bad the pain/pressure in my vagina is crazy. Every closing the car door is uncomfortable.  Any ideas ladies??? I didn't get a positive test but my periods are very irregular. Who ever knows.