"Every pregnancy is different"

I know they say every pregnancy is different but holy cow! I have a 9yo son and a 5yo daughter who were both fairly simple pregnancies. Im 7w4d today and I have the worst morning sickness! On top of that I am dizzy and exhausted 24/7! I have heartburn out the wazoo and my boobs feel like theyre full of lead! It makes me feel ssoooo guilty because we tried so hard for our third and final baby and now here I am so sick and hating every monent of this pregnancy so far! We go to the dr tomorrow so hopefully he can offer some sort of relief BUT it seems everyone prescribes phenergan (sp?) and I am so incredibly allergic to it!! Hoping that during the ultrasound we dont see two babies with how diff this pregnancy is turning out! Anyone else have a super diff pregnancy and end up being multiples? Im terrified!!