Could there be something wrong?

I'm 37 weeks along now and last night when I laid down for bed I started shaking, like shivering for no reason, I was not cold I just started shivering real bad (this happened to me only when I was in labor with my 1st) and then it went away after about 10-15 mins. Then my heart started racing and I just felt sick. Well needless to say I didn't get much sleep, I've felt sick all night. I've been dehydrated so I've been chugging down water but that seems to even make me feel sick. I have a DR appt. tomorrow but just wanted anyones opinion. Am I looking too much into this?