I'm on the implant with weird periods

I'm 16 and have got the implant, I had my first period since having the implant not so long ago and experienced excruciating pain with flesh like tissue clumps coming out in my period (only 3 clumps came out) I got worried and went to my doctor, he checked and said it was normal since it being the first period since having the implant and just gave me some iron tablets, I came off for 8 days and now I'm back on my period, is this a normal time gap or should I talk to my doctor ?