Breast feeding

My 3 week old is breast fed only.. she stays on the breast for 15-25 minutes. Sometimes she doesnt stop and I have to stop her because she throws up a lot after and is really fussy.. Im producing a lot of milk. After feeding her I usually pump because of engorgment. I get 8 ounces both breast together. Should I limit the time she eats? Instead of 15 minutes maybe 10?? I usually just let her on her own to finish but I'm tired of seeing her throw up.