Work - Do I need to give a notice period?

I work full time in the week but I have recently got a weekend job aswell.

I have not been at the job for a month, only 2 weeks, but already want to hand my notice in.

I have not been provided with a contract so notice periods have not been provided and looking on the internet I can only find that you need to give a weeks notice if you have worked over a month.

So what is the notice period if I haven't even been there a month yet? Or is there no need for a notice period?

Thanks