Is he teething by chance? That might affect how he's reacting or feeling.
I would just continue to offer your breast and pump when/if needed. I think he'll come back to it when he realizes this is it. Lots of cuddling, humming/singing would help. Have you changed your diet any? Are you drinking more caffeine or eating things you don't normally eat? Sometimes that has an effect on how the milk tastes. I'm just throwing things out here, can you tell?
I truly think that you just need to not give up, give it time. I breast fed my 3rd one for 18 months, best time of my life. I loved it. Giving him a year on the breast is IMHO the best thing for him. Continue to work with your lactation person and just relax.
Congrats on being a new SAHM, it's the best job in the world. I have 5 kids (well kids...heck 1/2 of them are grown but all living here). They are 9-22 and I have been a SAHM for 18 years.
Let us know how he does.