Freaked out after smoking weed

So I smoke weed at least once a week, and normally I'm fine, but today I was smoking, I got really high and we went to McDonalds. On the way back, my head started to buzz like really loud and my vision got so bright I couldn't see anything. This has happened to me before on multiple occasions with different factors every time and there's nothing in common, it just happens randomly. I fell down once because it happened when I was standing up, i blacked out and ended up on the floor. And I just can't see anything or hear anything and I'm panicking. I can tell what's going on but I can't function or talk, and when it starts to fade I'm covered in sweat, and it's really unpleasant. I was just wondering if that's happened to anyone else.