Seroconversion can be undetectable up for 6 month, the virus can go dormant up to that period of time and it can go unnoticed. 6-8 weeks,3 months is still too early to determine. You can go for an immediate checkup but do a later checkup after 6month as well.

I dont think you have hiv. The obvious early symptoms is having a flu within the 1 month period of contact. Dont think about it too much after you read this post though, cause sometimes the minds play tricks .