am i in labor?
It's possible that you're dilating a little, that's why the mucous plug comes out usually. I'd go ahead and have your care provider check your cervix tonight, right away. Labor contractions would normally be more pronounced and some cramps and soreness could be just Braxton-Hicks but this early it's best to catch anything immediately and not let it get to that point.
Also, before you go in if you need to wait a few minutes to get it organized, you could try lots of water to drink, resting, and maybe a few sips of alcohol if you aren't opposed to very light drinking in pregnancy.