Sorry you don't like your new job. Essentially, you need to look at your contract and see how many annual leave days you have per annum - divide this number by 12 (as in months in a year) This number is the amount of annual leave days you accrue per month.
So for example, I have 24 AL days per annum. And before any mentions it, yes I know the minimum is now actually 28 days per annum but I also get bank holidays so I technically get 32 and knowing my bosses if I mention this to them they'll start taking all the bank holidays out our AL entitlement with how tight things are at the moment. So, 24 / 12 = 2. Every 1 month I work I accrue 2 days annual leave.
I am guessing the whole months you worked are June, July and August and so you have earned 6 days AL (assuming you have the same). I would be surprised if they don't make you pay the one extra back.
On a side note, I would tread very carefully with not giving a full months notice of leave. Employers have the right to dock your wages the amount it costs to hire adequate cover to fill your duties/position for the amount of time you are cutting your contractual notice short by. But I've only ever heard of big corporate companies like supermarkets etc doing this.
Hope this turns out ok.