If you believe in karma, good deeds should give you good karma or luck, the Three Fold Law says that all the energy, good or bad, will come back to you three fold. If you're sure you've done good and no bad, you could have some kind of curse on you, though that's highly unlikely. In this case, try a protection spell(there are several in the spell section of this site) or try cleansing yourself. There are plenty of ways to cleanse yourself, ranging from as simple as a salt bath to a full spell. Again, look in the spell section of this site.