Need advice re: bleeding tonight :(

Hi Glowers,
I'm 12 weeks 4 days and am experiencing some light bleeding (red/pink) coming from inside my vagina. No cramping, I feel fine otherwise, and my 12 week ultrasound was good.
I called an advice nurse and she said spotting happens and if it were to become a spontaneous abortion, there's not much they can do. 
Has anyone else had spotting this far along? Did it actually turn out to be fine? It seems like there are a lot of different possible causes for spotting in the 2nd trimester, and none sound good. I'm not sure if I should be more aggressive about being seen by a doctor (it's late, so it would have to be at the ER), or just try to chill out (not easy). I hope you guys can help! Thanks.