I had something like that with my second daughter - it started out brownish, and turned dark red for a day or so. Scared me to bits! Turns out it was related to DTD - cervix was swollen and sensitive, and got "bumped" a little and bled. Easy enough to fix. Hope yours turns out to be no big deal as well. Also, don't stress too much about the cramping, as long as it stays mild, and the spotting doesn't increase. It's pretty normal to have some mild cramping, as the PP have said.
All the best!