Cramping 3rd Trimester 5th baby

So this isn't my 1st time around the block. This is my 5th baby and I'm 28wks. I don't remember ever feeling cramping like this late in pregnancy. I keep getting period like cramping. It didn't come in waves it's just constant. It's not contractions. It's not braxton hicks I get braxton hicks on top of the cramping sometimes. So the cramping starts either out of no where it after I've just walked around the house. I don't feel like I'm over exerting myself. I'm a SAHM and most of my kids go to school. I only have one that starts at home all day and she's pretty low maintenance. Most days I just chill in my bed all day and keep my activity to a minimum. I ask veteran so I have some back and hip pain. So I don't get why I'm cramping just from walking around or just going down the stairs. When it happens it will l last for a hour or more just constant pain. I have an appointment in 2days I'm going to bring it up but I was just wondering if anyone else gets cramps like this so late in pregnancy..