How do you know if you are having contractions

Ftm here! 36 weeks pregnant. Today I was at walmart with my husband and about 10 minutes into walking around the store i was getting very intense pains in my vagina. Like i had to stop and kind do a few little mini squats and take some deep breaths to deal with the pain. It was all in one spot in my vagina, not in my stomach, or uterus or anything. It happened intermittently throughout the store (about 45 minutes to an hour) and the car ride home and finally stopped when I got home and laid down. My husband has done a fair share of research because he is excited about the baby coming, here is convinced Its contractions. Im not so sure it is but im a little concerned with it. I have an apt with my midwife tomorrow but Im just curious as to what these might be or if im close to labor.