I think I lost my mucus plug! Advice please.

Caitlin • First pregnancy, excited and couldn't be happier :)

I went to the toilet yesterday and when I wiped a couple of times there was a thickish greenish mucusy discharge, I'm 34 weeks and I'm just wondering if that could have been my mucus plug or if it could have just been a change in discharge? I had some back pain and some shooting pains in my lower stomach aswell but they didn't feel like contractions, I feel better today but I'm feeling a little less movement from bubs but the last few weeks his been very very active, I have an ultrasound on Monday and a doctors appointment Wednesday, just wondering should I maybe give the doctors a call or something, or just wait I feel like I'm having contractions?

Is it possible not till realise your having contractions?

Sorry for all the questions, first time mum here and just don't want anything to go wrong.