Have you tried seperating this logic into a class with @future, and then calling it to do your logic asynchronously?

It now allows me to do it except the only problem is that the PDF is now coming out blank.

global class pdfCreator
{
    @future (callout=true)
    public static void createPDF(ID Id)
    {
        PageReference pdf = Page.AccountsPDF;
        Attachment attach = new Attachment();
        attach.ParentId = Id;
        attach.name = 'name.pdf';
        attach.body = pdf.getContentAsPDF();
        insert attach;
    }
}

trigger CreatePDF on Contract_Custom__c (after update) {

    for(Contract_Custom__c a : Trigger.New)
    {
    	Id id = a.id;
    	pdfCreator.createPDF(Id);
    }
}

 above is the code for my class and trigger

You probably need to pass in the ID otherwise the page doesn't know what it's rendering....

try the following if your page has a standardController for Account:

@future (callout=true)
public static void createPDF(ID Id)
{
        PageReference pdf = Page.AccountsPDF;
        pdf.getParameters().put('id', String.valueOf(Id));

        Attachment attach = new Attachment();
        attach.ParentId = Id;
        attach.name = 'name.pdf';
        attach.body = pdf.getContentAsPDF();
        insert attach;
}

I tried the fix above but unfortunately it is still returning a blank pdf.