Thanks, Kat -- my midwife did call back, and basically said the same thing. She said it's reassuring that it was intercourse that caused the bleeding, but maybe not so reassuring that I'm having mild cramps. An ultrasound would confirm whether the baby was okay or not, or we can wait and see what happens. I asked what I could expect if this does become a miscarriage, and she said the bleeding and cramping would likely get worse. Since there's not much I can do either way, I'm going to give it some time (until tomorrow) and see whether it worsens, stops, or holds steady -- and unless it stops, I'll call to schedule an ultrasound tomorrow. (She said to call her either way.)
I suppose I could have just scheduled the ultrasound right away, but really, I think I'm not ready to deal with a definite miscarriage situation. I want to hope, if that makes sense?