Are these contractions?.

I do have a 2 year old. However I was on a ton of medicine when I had her bc I had preeclampsia so I don’t remember 90% if my labor/delivery and none of my contractions. I’m currently 31 weeks and 3/4 days with my son. I know contractions come and go, but they always reference to me “how you feel when cramping during a period”. With that being said let’s get into me being a dumbass. The last few weeks I get burst of pain in my back and a tightness in the top of my stomach. These I thought of as braxton hicks. However, I’ve had a constant pain in my back for 3 days now. I’ll get a moment where it gets real intense and takes my breath almost along with a lot of pressure in my pelvic area and a tight feeling in my stomach. At first I only thought of the random intense pains as contractions and chalked it up to braxton hicks, as baby is head down. However the back pain that I constantly feel right now is what I feel when on my period. I don’t get cramping, I get a constant back ache that is super intense for the first few days and lightens until my period is over. This is the same pain I feel now, but not starting off as intense. This is what has me so confused. I feel a bit stupid not knowing what a contraction is supposed to be, but my son has an anterior placenta and a Velamentous cord insertion (which isn’t supposed to cause a ton of issues but it can and they can be severe) so I’ve been worried about if I’m missing the signs