I'll try and talk you down off the ledge a little, as I went through the same thing. You just have to think about it being a day by day thing, and today for you there's no good reason to feel so scared. You have good signs - lack of an appetite, cramps that are common with pg when your uterus is stretching, and being tired and having sore bbs. And importantly, this is a DE pg.
Unfortunately, being scared may not stop. You can ask anyone on the pink board this and they'll agree. Just don't let fear overwhelm you so that you don't think positively and enjoy this great time of your life.
Wishing you a wonderful ride home on Friday.