I get heat exhaustion very easily?

There was this one time when I was younger I got heat exhaustion when mini golfing. I felt sick and dizzy, it was hard to stand, and then my vision went black, I got that sometimes randomly when walking or standing and then it'd come back soon after, but it didn't that time and I freaked out, then everyone sounded echo-y, I was ok after sitting down and drinking water. But now I feel like I get it a lot easier afterwards, even just walking in the backyard for watering plants (in summer) and even now it's winter and I get dizzy and weak from just trying to clean my room. I'm 17 if that helps. I told my mom and she just keeps saying drink more water but that's like all I ever do lol is this normal?