Herpes or pimple?

I had unprotected sex 6-7 weeks ago. I have had no definite symptoms but am still worried about having any stds. A couple days ago I noticed a pimple on the shaft of my penis. It is slightly red but mostly flesh colored, does not hurt, burn or tingle, and there is only one (not a cluster). It is more of a bump that feels like a pimple more than anything. I'm pretty sure it's not a hair follicle because it's not close to any pubic hair and doesn't appear to have any hair trying to get out... (does this matter?).
I sometimes feel as if I have other symptoms of genital herpes (headache, lower back pain, muscle aches in my legs and arms) but still can't decide if it's just my mind playing tricks on me. They've been on and off for several weeks now even before the pimple appeared.

My questions are though, does this sound like an initial outbreak? As it would be a first outbreak would I be experiencing more pain or discomfort or more pimple like lesions on my penis? I guess what I'm trying to say is would I know if I had herpes even with a mild case or would it and should it be this tricky?
One more thing. Since it's been 6-7 weeks and I've read the first noticeable outbreak of genital herpes would happen within 2-3 weeks, does this help rule out an std?
I understand you can't diagnose me over the internet but any help would be appreciated.
Thanks