I just read your post from a couple of weeks ago to find out what's up with the weight loss (unknown, I see - not anorexia.)
I started off writing something about calling your doctor's office and asking to speak to a nurse to try to get a quicker appointment, but given your symptoms, I'd say just go to the ER. It's very likely that you may need IV fluids and would have to go there even if your doctor saw you today.
When you get to the ER, you know they do that thing where they ask why you're there to try to decide where to put you in the line of people waiting for help. (unless you get lucky and there's no line.)
When they ask you why you're there, tell them when you noticed the weight loss starting and your worst symptoms and that your regular doctor can't see you for two weeks. Hugs, sweetie. I hope you'll let us know what happens.
P.S. I see that you're 18 - don't know if you live with your parents. Since I don't know the story there, I can't advise on that.
Just please take care of yourself and get help, okay?