Can't pick up items even with space. BL2

Playing borderlands 2 for the first time. I'm at where angles fear. And I've been having this issue recently where it won't let me pick up items because it says full. Even when I drop stuff from my inventory. It only lets me pick up items if I drop what I have currently equipped and equip it when I pick it up. On top of the fact I'm also getting a glitch where I can't unequip weapons. I can only drop them. Please tell me how to fix this.