Sayang, beta HCG levels differ person to person and timing is really important here, some people start lower, some take longer to rise, so you can't compare with others! Tapi please see your doctor ASAP to check if this is a viable pregnancy or not, esp since your UPT only showed 1 line, don't guess-guess, let the doc do a scan and proper blood work to give you clear answers, ok? A few of my mum friends went through confusing numbers like this, and the doctor was the only one who could actually clarify what was happening. Waiting for your repeat on 8/3 is the right move, but honestly don't stress yourself with the numbers in the meantime, your doctor will explain everything properly when you see them.