Menstrual cramps and dark red bleeding 1 week 5 days postpartum?😨

I had my son on April 11, and for the first week I had the light, pinkish/red/brown bleeding and no cramping since maybe the day after I had him... Today I was laying in bed and I noticed some period like cramps in my back that radiated to the front of my abdomen... when I got up and went to the bathroom, I noticed some dark red bleeding (little heavier than normal but not soaking the pad) and when I sat down on the toilet I was passing long stringy clots.. I called my nurse and she said take a Tylenol and lay down for a bit, the cramps and bleeding have gotten much lighter, but they're still there and I'm still passing some clots. Any other moms have this and turned out okay? I'm so scared that it's something serious...