I started bleeding 7 days after period, red and brown. Crampy and sciatica previous fibroids!! ?

Old blood. What happened to your fibroids? If no surgery, likely still there to some degree which can cause irregular/abnormal cramping and spotting. The brown discharge is very likely old blood from your uterus/cervix/upper vagina and not that uncommon. May want to consider recheck with your gyn doctor to check status of fibroids and discuss other possible therapies.