Are characters supposed to gain only 1 or 2 hitpoints each level, after about level 3? I thought I was just getting bad "rolls," but my entire party getting them.

The pattern I have seen seems to be mostly 1 hit point except every now and then you might get a bunch, like ten or so. It bugged me at first, but it hasn't kept me from advancing thru the game, so I don't worry about it anymore.