I was at 50 miu last week and 686 today ( 6 days apart )

Went to OB, thinking I was about 6 weeks and she told me she thinks about 3-4 weeks. So at 3-4 weeks, is 686 high, normal or low for how far along I am?

My husband SWEARS he saw 2 on the ultrasound we did on Monday but I think he's nuts. We didn't get any pix but was told to come back in 2 weeks to do measurements since Dr couldn't confirm how far along I truly am.

Note : got IUD removed 8/30, started 9 day heavy cycle same day. Not sure if that was a period but Dr said she didn't think so. So totally unsure of when I ovulated.