help I'm worried!

I am 7 week 3 days I started with cramps the other day so came to an early pregnancy unit to check everything was ok - they tried a normal scan first but couldn't see anything so did an internal scan the scan showed two pregnancy sacks but one didn't look like there was anything in and the second just showed a tiny pin prick and the nurse couldn't find a heartbeat I have to come back in a week but I'm worried sick anyone else