I fainted my entire first pregnancy. If gets worse u may have to stop driving. Sometimes it can be from low sugar and sometimes you just faint. Talk to your doctor because I know it can be scary. With me I was fainting atleast 5 times a day so I have to take time from work, school,driving, and I every time I fell I'd have to go to the hospital to check the baby and they would keep me for a couple days. I hope it gets better soon
Let your doctor know, he/she should be able to provide you with nausea medication