My periods are generally 3 days long and with a heavy and painful flow the first day. It normally comes on gently. But there are times when I can feel it coming on and then all of the sudden it cramping comes out of nowhere to the point I feel like something inside of me has burst to the point I'm squirming and doubled over, can hardly walk in pain. Thankfully, pain killers and heating pad does work. I'm wondering why this happens occasionally. I'm glad it doesn't happen more often, I really am (cause that would suck to go through this every month), it's just odd. I was diagnosed with a cyst on my left ovary three years ago so I'm thinking that has something to do with it but it didn't start affecting my cycle until the past year or so. 🤷🏼‍♀️