I'm confused...sad and worried..

My lmp was Nov 1st. Dec 3rd I found out I'm pregnant. Yesterday I started spotting and today I am bleeding like if I was on my period no clots and hardly any cramps. I went to the ER this morning. Got a pelvic exam, abd & vaginal u/s and blood work. The Dr did say my cervix is closed. According to the app I'm 6 was 3days. But according to the doctor I'm 4 wks maybe 5. My hcg level was in the 300s. I'm going in on Tuesday to get my levels rechecked to make sure they are going up. If anything I thought I would have been 5 weeks at the least but not 4. 
This is my 3rd pregnancy. 1st time I had no bleeding whatsoever. 2nd some spotting a lil red but not heavy. I understand all pregnancies are different. Did any of you ladies experience something like this and have a normal pregnancy?
 I'm trying to stay positive because as far as I understand this it's a threatened miscarriage and it could turn out to be just fine. Praying that my lil blessing is well and I don't miscarry.😢🙏🏻