Confused?

Taylor

So we had a miscarriage feb 2018 (almost a year ago) and recently found out we were pregnant again. According to my last period, i would be 8 weeks and 3 days, but when we got our first ultrasound yesterday, i was measuring 7 weeks 2days. Heartbeat was a strong 140. I’m very nervous about what this could mean. Is it something to worry about? I’m afraid of miscarrying again