Any nurses here?

Shelby • 25 Years of Age, Due with my princess in June, Loss Of 3
So I've been bleeding on and off for three days now, it goes from brown to bright red back to brown all in like a five minute span. I'm 5w5d. Late at night I have cramps on my left side to where I can't move and it goes away if I take a hot bath. What could be causing the bleeding my hcg is 1100