Jess, that sucks, what the GP said! Male doctor... grrrr! I wish I could help ya, I have a freezer full of EBM and no use for it. Tried to give Aadi some today but he wouldn't touch it. Just wants to chew on the teat.
I'm drinking extra on these hot days and if I'm walking lots, but nowhere near 3 litres. I take a maternal multi-vitamin, iron and calcium-magnesium (when I remember, coz you can't take it with iron coz it prevents absorption), and I eat fairly healthily but that comes with being dedicated vegetarian for over 12 years. But I don't know if any of that contributes to supply. Everyone's different. I would be getting another opinion, tho, from other sources than doctors. Don't give up because of one guy's thoughtless comment. You're doing great to get this far, and hopefully you'll be able to continue, but it's not the end of the world if you can't.
As for the sooking, I know I read somewhere that teething symptoms can go for a few months before the tooth shows... could be that? All the babies at playgroup the other day were sooky too, so it's definitely a phase!
Hope everyone else is having a cool day. I'm feeling a bit wilted...