Pseudophedrine doesn't actually help you get over the cold; it just suppresses the symptoms temporarily. I use it only in dire emergencies, like when I have to give a presentation while I'm sick and don't want to sound terrible.

Otherwise, I stick to things that actually help to boost my immune system: Vit C and zinc. And exercise, when I'm feeling up to it. All three are powerful immune system boosters, and the zinc actually helps with the symptoms too (or seems to).