What Causes A Sharp Pain And Stoppage In Menstruation?

I have had an iud for the last 3 years. At work earlier I got a really sharp pain in my lower abdomen, and it would go away. That was 4 hours ago. When I went to the bathroom to pee I was bleeding. I haven't had a period in a very long time, since the IUD, if I spot at all its barely anything. This isn't a constant flow, but very think dark red clots. I feel a little light headed and the pain is still there, just not as intense. What should I do? I don't have any insurance, so don't want to go in if I don't have to?