Experienced Mamas! I need help

I had contractions on Sunday that were decent but not horrible. The pain radiated throughout my back so I figured they were real and they were! But I was 35 weeks so they gave me a shot to stop them. I've had a few on and off since then. But today I lost about half of my mucus plug and I'm wondering can I go into labor soon? Anyone ever had this?

I was also very nauseous and had an upset stomach last night for about 30 min and then it went away. I haven't been sick my whole pregnancy.