Please help.

I've been losing bits and pieces of my mucus plug, nothing with blood or anything like that(Sorry TMI) for the past 3 days. I am having bad cramps on and off throughout the day that sometimes double me over and severe lower back pain. I am staying nauseated and lightheaded. Does anyone have experience with this or know what could be going on? I'm not sure if I'm having contractions or not. I'm having pain in my thighs and I just feel horrible.