Microscopic condom pores or leaks that allow HIV to pass are an urban myth. Unwrapped or outdated condoms might be more likely to break, but if they don't, protection is complete.
So I shouldn't worry about the condoms being somehow contaminated.
Earlier today I started to feel a slight irritation (maybe a slight burning sensation) in my penis. Now I'm starting to think that perhaps the condom had a small tear in it. When I pulled out of the CSW, the condom seemed intact but I didn't inspect it very closely (i just removed it with some tissue paper and threw it away). Is it possible for a condom to have torn in the way I described? I'm really freaking out. Please answer somebody!
"Is it possible for a condom to have torn in the way I described?" No. And your symptoms sound psychological.
Two days after my experience I started feeling the slight irritation (maybe burning) AFTER urination (not during) which is why I'm afraid I might have contracted trichomoniasis from the event. If I did, doesn't that mean the condom must have failed somehow and that I was exposed to HIV or some other STI? I'm really worried and plan on getting tested at the end of the week. How soon do symptoms trichomoniasis appear anyway? I started feeling the sensation Saturday morning (my event with the CSW happened Thursday afternoon).
You don't have an HIV concern.