No, it is not conclusive for HIV. For that you need an HIV test which is a blood test. You can take it now and it will be conclusive for HIV.
I have taken a urine test recently for STD's and my doctor said I had Chlamydia and nothing else so is that conclusive?
Any time you have unprotected sex, there is a risk, therefore you should be tested. A test at any time now will be conclusive.
Your overall risk is low in this scenario, but a risk is a risk.
Your college blood work would not have included an HIV test, and yes, while it's true that MOST pregnant women are tested, you don't determine your risk by someone else's test.