Bleeding at 15 Weeks Pregnant?

So I woke up this morning feeling totally normal, no worries or anything. I had to pee really early and I didn't notice anything, of course this could be because I was half asleep. Just a bit ago, after getting dressed and having my coffee, I noticed some blood on my underwear, it kind of reminded me of old blood that you get just at the start and end of your period. It's mainly on my underwear, when I wipe I get a bit of a tint, but nothing gory, like when I wiped with my period. I had a bit of cramping last night, which I basically attributed to the huge dinner that I ate and it causing gas. My ob/gyn won't be open til about 8, and it's military health care, so the only other people I can call are the emergency room. I know I've read that some women have bleeding in pregnancy and no problems, but I need some words of wisdom here! Thanks for anything!