iPhone 4 e-mail sending and updating very slowly

I am using an iPhone 4 that up until this morning was running perfectly. However, today my e-mail is updating/connecting very, very slowly. I am connected on a 3G network at the moment, but typically even on my 3G network, e-mails send very quickly and my e-mail updates very fast and efficently. Today when I send an e-mail (even just a short email to "test" it) it takes between 2-5 minutes to send. Getting e-mail updates works, but it is also very slow.

I have tried deleting my email account (I'm using a gmail account) and reinstalling it.

I have also tried doing a hard reset of my phone (holding down the home key and the screen lock key until it turns off, waiting a few minutes, then turning it back on).

Any help or suggestions would be really awesome.

Thank you in advance.