advise please

I have only had 1 baby in 9/2015 it was a c - section , I found out a few weeks ago that I I am pregnant again and more than excited for the last week however I've noticed a heaviness feeling , like cramping as if I'm going to have my period , and long behold a good amount of old brown blood came out , sorry for TMI , I have called my doctors and the nurses tell me it's normal for spotting to occur but I don't feel like it's spotting , now it's still to be brown but looking more mucus like ... I've called several times to my doctor and have waited since Wednesday for a call back to be seen😔 I don't want to believe it could be a miscarriage . Has anyone else had this issue and pregnancy was ok? Please let me know