Can HIV go Undetected even with Testing?

I had an HIV test done thursday but will not get my test results till monday.

The reason for this test is because a ex bf who I have not seen in almost two years messaged me claiming I gave him HIV but the thing is I was only with one person before him and that was my sons dad and I got tested while pregnant and after having the baby the only person I slept with was my ex bf and he joined boot camp a year later then entered the military and for both boot camp and military you get a physical which includes bllod test for all STD's and no HIV ever showed up and my sons dad was in the military and I was never told of him having HIV and I would of been told if my sons dad had HIV and it would of show up in my test when pregnant.

I am just a little worried and shakin up, my doctor keeps sayign i do nto have it because thier is no way the military would of missed it twice.

Am I worrying myself for nothing and everything will be fine?