Help Captivate e-mail doesn't work while connected to Wi-Fi

[megajos]

I have been having trouble with my e-mail since I bought the Captivate a couple of weeks ago. Sometimes the e-mail will come through to my phone within seconds, sometimes it takes hours and sometimes it never comes through unless I shut down and restart my phone. I originally thought it was happening all the time but I now realize that it only happens when I am connected to Wi-Fi. I literally can send myself a test e-mail thats will come right through and then turn on Wi-Fi, send myself another test e-mail and the e-mail won't come through until I reboot the phone. My e-mails are set up through G-Mail and I have used both the stock e-mail app and mailDroid and it is the same on both. I was starting to think that it may be my router but my wife's iphone works perfectly. If anyone has any suggestions I would appreciate it. I haven't seen anyone else with this specific problem. Thanks.