If the spring is going bad that quickly, then I would look for misalignment on that spring, either the spring hangers are set incorrectly, or the frame is twisted in that area. I would take it to a compentant alignment shop that is familiar with trailer axles and have the alignment checked. Also tell them about the problem that you are having and they will look for a potential cause.
03 Silverado cclb 3500 drw, D/A, Reese 22k hitch
07 Alfa SeeYa Gold 30RL,2 slides,power everything