Am I Paranoid?

Hi there,
I understand your concerns in this situation. But I see hiv risk as quite low. Firstly, lets consider protected sex. It is generally, and reliably, acknowledged that if the condom is used properly and remains intact, the risk of infection is essentially non-existent.
Now, your only concern is whether the condom was a reliable brand. This, i'm afraid, you won't be able to know for certain. I would suggest however that as a 'professional', she is likely to use reliable brands in her own interests - but this is mere speculation.
Additionally, you say there may have been lubricant because you couldn't feel her vagina. Did you not notice her applying any? It would be quite clear whether she did. Not to put to fine a point on it, but it is likely that, as a prositute, her vagina may be quite, well, 'roomy'. That said, a word on lubrication - if indeed she did use some, and it was oil based, then this will damage the integrity of the condom and i'm afraid there will be some level of risk for infection. If it was water based, then there isn't a problem since the condom will remain totally safe.
On to your symptoms. Firstly, I think a week is a little too early for initial hiv symptoms to begin, but that is not a steadfast rule. You say your temperature was 37 - 37.4 c. This is a perfectly normal body temperature and within normal parameters.
I would say that your risk is really quite low in the scheme of things, and your symptoms are not a reliable indication of hiv at all. Everyone gets sore throats. However, if you are in doubt about the integrity of the condom, then take a test three months after the incident occured. All in all, to be totally safe, I would reccomend that you test. I wish you well, but I think you'll be fine really.