Passed out / fainted 17 weeks pregnant

I passed out today at 17 weeks pregnant. I had just eaten about an hour to an hour and a half before hand and like 30 minutes before this I had 1 starburst plus like half an iced matcha from starbies which has a good amount of sugar, I wasn’t feeling bad at all leading up to fainting but all of a sudden I felt sick , hot , lost my vision and hearing and ended up on my ground ( fell to my knees then face thankfully not on my tummy ) I chugged 2 large glasses of OJ and was functional again. I have low blood pressure naturally and I find it hard to believe my blood sugar would get so low so fast. It’s the weekend and I can’t contact my OB but what are the reasons this could have happened and what can I do for the future as this came out of no where and was quite scary.