Low milk supply! Please help!!

So my son is 2 weeks old and exclusively breastfed and I think I have a low milk supply. I don’t know what to do to help increase my supply, I feel like I’ve tried everything!

It’s important to note that I had a low supply with my first son too, he’s now 2. I never produced more that 2-4 ounces combined a day with my oldest son and had to supplement.

This time, I can tell I have a low supply because my son is constantly wanting to nurse but getting frustrated at my breast. He’ll latch on, suck for a few seconds and the get mad and start crying. It’s an endless cycle of trying to get him to stay latched. Eventually he just falls asleep and wakes up 20 mins later crying cuz he’s still hungry. He does eventually latch and seems to get some milk for maybe 3-5 mins and then you can tell he’s not getting any more milk after that. I use the Haakaa on the breast hes not nursing from, I hardly even get a few drops from the haakaa. When I pump, again, I only get a few drops. I know that what you can pump out isn’t always a good indicator of your supply but with all the other signs, I’m pretty sure my supply is low. He does have a decent amount of wet diapers but he’s only gained 1oz. We have an appointment in a week to see if he’s gained more and that will tell me for sure if he’s getting enough milk. I feel like he’s not gaining weight but you never know I guess. I’ve had to give him a few bottles and pump every time he has a bottle, just to make sure he’s not starving.

I eat oatmeal with flaxseed, peanut butter and almonds every morning, I drink a TON of water, I use the Haakaa every time I breastfeed, I try to pump after each feeding (but I get nervous that he’ll wake up soon after and want to nurse but there won’t be any milk because I pumped it all out so I don’t do that often), I do compression and massaging while pumping/breastfeeding which sometimes helps. I don’t know what else I can do. Please help!! I reallllyyy want to be able to exclusively breastfeed him. 🤞🏻