Early ultrasound

So I am still not sure how far along I am- here is how my beats have gone so far

01/19- 25.6

01/22- 57.6

01/24- 146.6

01/29- -1641.0

This is my first pregnancy and I have obviously found out very very early which is making me worry- I had an ultrasound yesterday and this is what we saw- a sac and possibly a tiny yolk sac- the doctor didn’t seem concerned but also couldn’t really tell me how far along I am and said I should have another u/s in about two weeks. I am just worried because I found out so early I have so long to wait to find out if everything is going well- anyone out there that can relate?