Bleeding 7weeks postpartum

I was bleeding after I first had my son, but when I got home from the hospital the bleeding started to get lighter and lighter and by almost 6weeks it had dwindled down to just spotting of light pink blood. I told my doctor that I was still bleeding at my 6week checkup and she didn't say much but just that some people take longer to bleed. Well just a few days after that appointment I started bleeding heavier again. It's nothing like the first few days after giving birth,but it's like the flow of having a period. I know it's not my period because it would have ended by now if it was my period and it would have started tapering off each day getting lighter and lighter. I am breastfeeding too, so I know most women who are wind up getting their period later. I asked the nurse about how I am still bleeding a few days ago, as she had called me to let me know some labs results and I wanted to ask her about the bleeding while she was on the phone. She wasn't concerned and just said some women take a few more weeks to bleed. It could stop one day and then I could have bleeding the next. Well, the bleeding still hasn't stopped and it is bright red and still having a good amount of bleeding. It's starting to concern me a little bit but my doctor and nurse were just so chill about it. Do you think I should call them again and push that they do some sort of ultrasound or something or should I just wait until my annual appointment with them in three weeks? Anyone have similar experience and just bleed for several weeks after giving birth and everything be ok?