21w6d--Red blood!!!!

The scariest things happened to me again today. I was at my mom's and we were in kitchen making breakfast. Suddenly, I felt a strong cramp/pain/twinge, whatever you want to call it, on my left side. I put my hand over it hoping it would go away. Out of nowhere, I felt a gush come down and I ran to the RR. I wiped and there was red blood! Once again, I freaked out. I wiped and continued wiping and the blood kept coming out! I was terrified. I tried to keep calm, put a liner on and told my mom I was going to lie down for a bit because I was bleeding. She panicked a little and then tried to console me telling me that it was probably just like the last times and more than likely it was nothing. I did absolutely nothing the rest of the day, but lie around. It lasted about 15 minutes and then changed over to brown flow. I was more like a light bleeding, but brown, rather than red. I seemed to be less and less as the day passed. The cramp in my left side continued and that was what worried me the most. I called OB on call and she said to just rest and call tomorrow for an u/s to check everything is okay.