Dizzy if I don't eat frequently

Does anyone else feel extremely light headed- to the point where I legitimately almost pass out- if I get too hungry and don't snack between meals? It's happened about 4 times now (I'm 15 weeks), but I've just had to rush to get something to eat. I never skip meals but if I don't snack, I get like this. I'm assuming it's probably low blood sugar, but I've never gotten like this before I was pregnant. I haven't been tested for any diabetes/gestational diabetes yet, but is this a sign, or is this completely normal? I go to the doctor on Monday so I do plan to mention it.