Headache after hard sparring - exhaustion or concussion?

[mozilla2004]

I'm an amateur boxer. I spar about two times a week. My conditioning/endurance is maybe average, or slightly below average compared to other amateur boxers. Each sparring session is 10 rounds of 3 minutes each. The first 4 rounds are light to intermediate intensity where my opponent gets all weapons but I only get jabs. The last 6 rounds are high intensity where my opponent continues to get all weapons, but now I only get to body shots ( I can't use jabs anymore). We break for 1 round between round 7 and round 8.

In the last month or so, I've been starting to get minor headaches towards rounds 9 and 10. Even when I block my opponents jab, my head aches a little bit. My defense is fair. My opponent hasn't yet landed a clean heavy shot to my head. My opponent lands a lot of punches on the gloves blocking my head, which then passes the force to my head. My opponent has improved compared to 4 months ago. Because 4 months ago, I didn't have to work as hard, and I'd still feel pretty fresh after 10 rounds. But these days, I have to work really hard from round 5 to 10 and there are times when I just have to give everything I have. By the end, I just want to lie down and sleep.

So before, I never use to get headaches. But now that my opponent has improved, I'm starting to get headaches towards the end of sparring. The headache goes away a few hours later after I eat something and take a nap.

Is my headache caused by exhaustion+dehydration or is it actually head trauma?

I should also add, i'm still very new as amateur boxer. I've only had 2 amateur fights.