What to Expect When You Don't Know What to Expect

I'm just getting home from a 6 hour ER visit. I took two digital pregnancy tests on September 30 and October 1, & each was positive. At first I was shocked. Then I was scared. finally, my SO and I are excited. Unfortunately,  I've had cramping and my doctor sent me to the ER w/ tubal pregnancy worries. Long story short: They took blood & did an ultra sound.  The pregnancy is in the very early stages, looks like it could be in the uterus, but they need to see if my hcg levels go up in 48 hours. I had my first visit scheduled for tomorrow... Once again I find myself shocked and scared; my excitement was stolen. I'm also confused, because according to Glow I'm 5 weeks 4 days. Shouldn't my levels/baby be high/large enough to detect? This is my first pregnancy, so I don't quite know what to expect.