36 weeks 4 days and might be in labour 😲

My last check up at 36 weeks cervix was very "thin and mushy" is what my OB said and she could already feel his head. I asked if I've dilated and she said not yet. I've been having braxton hicks since about 34 weeks but last night they became a little more intense and every 13 min or so. I woke up with period like cramps as well and lower back pain. I am scheduled to have a C-Section at 39 weeks due to incompetent cervix (abdominal cerclage in place)*cannot deliver vaginally. I called my OB and the OB that is in for her said to call once I have pains every 5-7 min. My sister told me with her second child she was just having period like cramps with back pain and she went in for regular check up and she was already 5 cm dilated 😱. Is anyone going through same pain experience? Attached picture below. I think I might be #2 if anything now.