Hi Megs,
Just wanted to offer my sympathies, as my LO also has reflux and I've been through much the same as you. I exclusively breastfed until 11 weesk (he was hospitalised at 9.5 weeks where they diagnosed reflux as a reason for v. poor weight gain (still only 9lb 2ozs then). He was put on ranitidine and domperidone, which I think are mentioned on the reflux 101 page (if only I could find it again on here). We have to give these 3 times per day before feed and wait 20-30 mins before feeding after giving it (very traumatic period 3 times per day), after 2 weeks of this, he had still only gained 4ozs, so was put on formula top ups - 1 week later had gained 1lb and 2ozs in a week!!!!! So, have continued breastfeeding with formula top up morning and evening (e.g. 7am feed and 6.30pm feed - he goes to bed after this one). We have also been prescribed a hypo-allergenic formula as he had blood in some nappies, which can be symptom of dairy intolerance. Dairy has been listed to exacerbate reflux, so cutting this out of your diet might help, but you should consult dietician before doing so. So, I don't eat dairy, he has this formula and the meds and it seems to be helping, although we have just had to ask about upping meds due to his weight gain and if I hadn't asked about this, doc would not have done anything.
Anyway, guess my suggestion would be to try to give gaviscon before feed (you can get syringes at chemist), which really help or ask your doc for other medication and to see if you can get by with forumla top ups to breastfeeding. I still have to feed very regularly, e.g. 6.30am, 9am, 12pm, 2pm, 4pm, 6.30pm, 10.30pm, 2am (and sometimes 4am in between) - but it seems that little and often feeding helps - also BW stuff has been invaluable in determining pain/tiredness cries from hunger as the last thing a reflux baby needs is to be fed when hunger's not the problem.
My LO is now 16 weeks and at last weigh in was 11lb 4 ozs, so going much better. Also is incredibly strong, which is characteristic of reflux babies - just think how strong your little one will be growing up!
I really hope that helps - main thing to say is sympathies

Also, Mother and Baby Magazine (UK) had an article on reflux in January edition, (which was on sale in December) and you might find info on their website.