I agree with midori and palestrina - if you don't want to stop, you probably don't have to, as long as you get yourself some good support and stay positive.
Why are you expressing? Will LO latch on at all? Ideally, if he'll latch on, just let him feed feed feed and your milk supply will sort itself out for his needs.
If he really won't latch, then consider switching to offering top-ups from a cup. This way he won't be sucking from a bottle and hopefully will latch on a bit more readily when he's ready (this is what we did with my LO, who wouldn't even open his mouth for 8 days after being suctioned at birth)
How often are you expressing? I was told to express every 2 to 3 hours during the day, and every 4 hours at night in order to establish a good supply. If you pump this often, even if you only get a small amount per time, the amount will add up quite quickly. Remember as well that babies actually have really tiny tummies. They're born with a capacity of around 5mls, which goes up t0 15 mls over the first week. A BF baby, on average, doesn't really drink more than 4 ounces of milk per session. The volume of formula that babies drink is just because formula isn't digested as efficient as breastmilk, so more is needed to get the same nutrients. Breastmilk is super easy to digest, so the volume per feed can be less.
I'm a bit surprised by the posts saying to just give up and not to worry. You obviously want to BF, and there's nothing wrong with that! There isn't anything wrong with formula, but if you don't want to FF, I don't believe you have to.
Contact La Leche League and NCT and find a local BF consultant (google is your friend). If you still switch to FF later on, at least you'll know you gave BFing your best shot.
However things pan out, good luck