Hi there
Congratulations on your baby. It's positive that you are seeing a bf counsellor soon but I think it would be helpful for you to chat to one today.
The national breastfeeding helpline opens in about 90 minutes on 0300 100 0212
www.breastfeeding.nhs.uk/
You will get through to a counsellor in their own home.
They will ask you questions about his nappies, his behaviour during the feed, is he back up to birth weight, your comfort levels, how you manage breastfeeds (i.e. one sided or two sides? When do you switch sides?)
Pulling at the end of the feed at this age could be wind as you suggest. It might also be his way of saying, 'this flow isn't fast enough anymore. Other side please!' It could also be related to the latch not being great and he's a bit frustrated. It might also be overtiredness at this age. Or he is pooing.
Bottom line - if he is pooing about 3 times a day (poos the size of a £2 coin or bigger) and you are getting 6 obviously wet nappies in 24 hours and he is back up to birth weight, then he is very very likely to be getting enough milk.
DON'T feel like a failure. Reading a newborn baby's cues is bloody hard and EVERYONE finds it tough. It just takes time for you to get to know each other. You will get more confident.
If you ring the helpline they will troubleshoot and run through a bunch of questions.