Drawing blood question

So I'm almost 9 weeks pregnant, I've given a lot of blood and had my blood taken a few times with no problem but my first OB appointment, they took my blood and I fainted. They didn't take much only like 4 little tubes. I thought it was because I hadn't eaten , low blood sugar or something. But I went to the ER yesterday because I was spotting and almost passed out again when they took my blood , again not much at all and I had eaten . Anyone else like this after becoming pregnant or am I just crazy?