Low HCG levels at 6-7 weeks - what are my chances?

Catherine

First baby here so freaking out about everything. First bloods were fine, second one doctor rang me to say they were low and wants me to get an ultrasound. Booked in for tomorrow. Trying to prepare myself. Symptoms have been strong and continuous - what are my chances? Would love to hear from anyone who was/ is in the same boat - good or bad.

UPDATE: US yesterday - baby measured 7w0d with a heartbeat so all is normal and well :-). So relieved.