Pregnant and light headed 😨😨😨

I'm 8 weeks and 3 days pregnant and yesterday I started to feel light headed and felt like I was about to faint. But today the symptoms got even stronger.

Just a few minutes ago while I was in the kitchen standing up making a sandwhich... the lightheadedness hit me... and I all of a sudden felt very hungry (like I was starving) it was so weird because I've been eating at least 2 meals a day and snacking in between meals ever since I found out that I was pregnant a month ago... and I also felt like I was about to faint again.

I knew I wasn't going to be able to stand up for long (because I was about to faint any minute) so I rushed with making my sandwhich so I could hurry back upstairs to lie down in bed. But I struggled to make it upstairs because my legs were so weak and they were slightly shaking. Now I'm lying in bed but only my hands are slightly shaking and I'm just trying to take deep breaths to calm down.

I don't understand what's going on... because I've been drinking water regularly and taking vitamins (Geritol multivitamin and Women's 1 A Day multivitamin) since I found out I was pregnant a month ago. What could be wrong? Should I go to the ER ? My first prenatal appointment with my OBGYN isn't until this Friday October 13th.