It could be a miscarriage or it could be nothing. I've had two ectopics, one miscarriage and am now 38 weeks pregnant. I had light bleeding with all of them at the start. And, horribly, there isn't very much that anyone can do if it is a miscarriage.
If you start bleeding heavily then definitely go to A&E. They still won't be able to get you a scan until the sonographer is back after the weekend, but don't let them fob you off without agreeing to one either.
If the bleeding remains light, then you could go to A&E anyway, but, you might find yourself waiting for a long time at the hospital - on a weekend bank holiday, this is not much fun. Your GP may also refer you for a scan too - if your GP is usually fast at giving appointments then it might be worth waiting for them.
Whichever you decide, the best advice I can give is to stay off your feet, avoid any heavy lifting, and rest. If you have been quite active then a miscarriage still isn't your fault, but you should look after yourself - don't do anything that you might irrationally end up blaming yourself for later, in other words.
I hope you're ok. Bleeding in early pregnancy is horrible, and there's nothing you can do at this stage but wait. I've got everything crossed for you, and I really hope the bleeding has stopped.