Feeling Scared.

So on Tuesday I'm thinking that my period came here to do whatever she has to do for these couple of days, I was doing a little lite bleeding until I had this feeling of wanting to PUSH, when I say I had to push I had to push. I really wanted my husband to stop the car and let me get out squat and push.... I couldn't understand why I was feeling like this. I had clots the size of a quarter, nickle and dimes... My pain was HORRIBLE! I couldn't even sit down on my "Purse" I felt all weak and just tired, the pain in my back was horrible then it came down to the back of my legs and in the front I couldn't eat nor sleep... I finally got myself to sleep when I went to the bathroom and the bleeding was gone almost and the clots stop being so big. Could that have been just a regular period or a miscarriage but I don't think that I am pregnant. Need some advice