Hcg levels, bleeding, baby #2

I'm 6 weeks pregnant according to lmp. However I feel I'm probably not that far along, as that's how it was with my 1st son. I had some bleeding after having sex with my fiancé the bleeding has slowed down and I have received the rhogam shot just in case since I am O-. My hcg levels are going up but kinda slow, which is also why I don't think I am actually 6 weeks. See pic. The ER Dr told me I'm a threatened miscarriage but that doesn't mean I'm miscarrying could just be I'm not as far along. Anyone else experience this? Going to set appointment up with OB this week as my family practice DR doesn't do OB anymore, she was my OB for my son (he will be 3 in July)