how many drinks were you doing
I do at least one protein drinks a day (often 2) and don't have any issues
I pretty much only use Beverly International UMP
I also use IsoFlex Whey but I don't make drinks. I just mix one scoop into cream of buckwheat hot cereal
Averaging 2 a day, some days were 3, some days were none.
It was like as soon as I drank it, my body absorbed the water immediately (which it should) and left behind a "clump" of protein powder sludge that just sat there. If that makes any sense.
I use Beverly now and have no problems. But then again, I don't drink it either. I make pudding with it for late night dessert and my own protein bars to take with me when flying to a gig that is overseas. (Hate airline food). I think that actually putting it in with something of substance helps with the absorption problems. Since it takes longer for the whole intake to break down.
But even now, I rarely use it. One tub of Beverly lasts me about 8-9 months.