Girls, after childbirth, my bleeding stopped 40 days later. Then it was…

Girls, after childbirth, my bleeding stopped 40 days later. Then it was clean. Now three months have passed, and now I found light brown discharge on underwear, like a smear. And then there was a little feeling as if during menstruation the body starts preparing, because the stomach begins to ache slightly, but strongly, for a few seconds. Has anyone had this too?