Help!! I don't know if I should go to the hospital

I have been in early labor since Saturday. I went to L&D Saturday evening and I was dilated 2cm, but sent home. Since then I've had nausea, loose stools, and been very lethargic. I couldn't sleep much the last couple of nights due to discomfort. This morning I woke up to go the bathroom and lost my mucus plug. As soon as that happened I have been having constant back pain for the past few hours. Advice please!?