Wait a few more days and see. If you still don't start, you should really take an at home test. (They have them at the dollar store if you can't afford the expensive ones. I'd buy at least two, just in case one of them is a dud..) If you take the test, and it says negative, wait a bit longer. If you still don't start your period, you should probably go to the doctor to get a blood test.
Honestly, sometimes your period can go funky and come and go randomly. It depends on how your hormones are doing. When you just start to get your period, it can be a bit out of wack. I don't know how old you are, so I'm not sure.
BUT DO NOT, I REPEAT, DO NOT WAIT TOO LONG. If you are pregnant, you'll want to know early.
It's better to go to the doctor, and realize it's just your hormones or something, than to find out you're pregnant three months later.
I really hope this helped. If you need anything else, just e-mail me, okay?
iliketotickleunicorns@gmail.com
Author's response
Thanks :) good to know that dollar stores have them. Thanks again :) this really helped