Seeking advice on possibly stopping Judo due to concussion symptoms

I just started Judo in July. I know how to do all Ukemi correctly, including the forward roll, but for some reason I just can’t apply it in practice and keep getting concussion symptoms such as tiredness, dizziness, blurry vision, etc.

For example, last week we practiced a throw where Tori put his head under my armpit and fell on his side and he fell so fast I couldn’t do a forward roll and I landed on my head. I saw stars for like a minute afterwards and was dizzy for the next five minutes.

I will say when I first started Judo this occurred more frequently and I’ve gotten a bit better at falling but I’m worried that it’s still happening. I don’t want to end up with brain damage or anything.

I did go to a doctor in August when this first started happening and they said I likely had concussion symptoms before but was fine at the time.

Should I just stop Judo permanently or go less frequently or practice more Ukemi or something else?