Fainting spells during first trimester?

Is it normal to feel lightheaded and fainting spells during your first trimester? Other symptoms I experienced include feeling shortness of breath, dark vision, breaking out in full sweat, and heaviness of body. It gets better after I’m seated with my head low, but it just doesn’t feel good. I have history of low BP in the past but this usually only happens like once a year, but now it has happened to me for the past 2 mornings while I’m in the train commuting to work. Should I be worried? Does it warrant medical attention? #firstimemom #firsttrimester