If i don't take sudafed before a flight my ears drum will perforate how normal is this, what can i do?

Several things: Not normal, its eustacion tube dysfunction, the tube between nose and ears to balance pressure. Mucinex, (guaifenesin) chewing gum, lots of water, and saline nasal rinse all help as well.

Very abnormal : It sounds as if you have very abnormal ear drums with thinned delicate area that are easily injured by pressure change. You should see an ENT doctor to have your ears evaluated and possibly even have tubes placed to prevent spontaneous perforations which could ultimately lead to permanent hearing loss.