I don't lose things as much as you say you do, but still lose them enough times to make myself loathe myself. I am pretty sure that you need something like CBT, to learn coping strategies, and so you don't rely on medication that much.
It must feel awful to have people laugh at you for forgetting your stuff. People don't laugh at me and I end up crying after I lose something, so I can totally feel what you must feel when others laugh at you. It is like they are oblivious to how they can have an effect on you, and it makes you feel as if you can't make them understand what is really going on. The frustration builds up, and you just give up on trying to convince people.