Low potassium but side effects to supplements

So I've had low potassium multiple times this year. 3.1 the lowest but usually around 3.3 when it drops otherwise. Problem is that when I'm given oral supplements or IV potassium it causes severe constant presyncope and a flare up in pots symptoms even though I'm not overdosing on potassium (it never goes higher than 3.9). My potassium is low again and I'm scared even a small amount of supplementing is going to send me into a long presyncope flare that I can only partially get out of by having IV fluids. I don't want to end up in hospital again! I also can't tolerate coconut water with my stomach, I know that's a really good source.