If you are hit on your head, but did not lose consciousness, is it safe to say you don't have a concussion?

No. It's entirely possible to get a concussion without losing consciousness. One time I was walking across an outdoor basketball court when somebody threw a ball that hit my head. The ball then knocked my head into the wall of the school. I was conscious the whole time, but I had a nasty concussion.

No. You do not need to lose consciousness. Concussion symptoms include nausea, headache, dizziness, confusion, inability to find words when speaking.

Losing Consciousness has nothing to do with concussion , so no its not safe to say

no cause it is still possible

no it isn't

nope.

Loss of consciousness may occur, but is not necessarily correlated with the severity of the concussion

Generally that's true, but the real test is the presence or absence of neurological symptoms over the next 24 hours. Blows to the head can cause bleeding or swelling that don't cause any symptoms until hours later.