Thanks all for the replies. My 6 week doctors check isn't till Tuesday so it'll be interesting to see what s/he says. I did try the holding off just to see if she fed any less and after one day of it I woke up with sore leakier than usual breasts which made me worry about mastitis as it felt a little hard in one side and although she did fine with dummy and looking at things by the time I was preparing to feed her (suffers from bad gas so I need to get her medicine) she was screaming. Needless to say never again will I try this!
Anyway I started reading more online and all the symptoms of oversupply sound just like my little one: feeds frequently, gags and stops during feeding, burps like an adult, has gas problems, likes to suck her fist and the key one GAINS WEIGHT RAPIDLY. I think today I wil try and find the number to the local or national breastfeeding support and see what they suggest and talk to my doctor about it on Tuesday.