Your son's primary source of food should be from you or the bottle. I know that if you wean now you are still goign to have to give him forumla then until he's 12 months b/c that should be his primary source. Do you breastfeed before offering solids? That should fill him up and not eat as much for those meals. Also, how is the place that you nurse? I know now (my son's 10 months) that I have to be in a VERY quiet place with no distractions, no people or animals, and the lights have to be dimmed for him to eat. You need to initiate the feedings too. Don't wait for him to want to b/c they're too excited by the world to stop what they're doing. If you set up times and the places they will eat. It just might take a couple days to establish a type of routine. Is your boy eating at night? He might need to just for the closeness, etc. so don't limit that. Alot of times what I thought was weaning was just a growth spurt or something else and he'd nurse for an hour after all that fuss!
Don't give up though! There were a few times that my son has refused to nurse for long periods of times and it's just been the environment, teething, sickness, etc. Sometimes it hurts to eat or they don't want to stop what they're doing to relax to eat. Don't give up right when they refuse either, I've had to switch positions a few times and switch sides in order to show him that this is what we're doing.
Have you tried not giving him as much food during his feedings? A couple bites and then that's it? After all, it's not supposed to be his primary nutrition that's from you this is just showing him there are other foods out there and getting him used to it. Also, try to increase your milk production (pump even when he doesn't nurse) b/c you might be decreasing and it might be too much trouble to get the milk out for him. Any medications you started taking? Might lay off them for awhile. This site also helps w/ low milk supply.
This site has really helped me w/ everything due to bfing. I think these 2 sites will help you 2!
http://www.kellymom.com/nutrition/solids/solids-how.html
http://www.kellymom.com/bf/weaning/babyselfwean.html
GL and let me know what happens!