I am quite confused on what the cause of the problem is. My contact form had been working for a long time, then I got an email today which was all blank, so tried to test it, and it does not send an email to my gmail which i use for business. So I changed the email on php script to my personal one i use for gmail and it worked. I haven't changed any settings for the gmail account that i use for business.
This isn't really an HTML or Web Design topic, this is more of a systems administration or server-side programming topic. Anyway, check your servers mail log to see if it's reporting any errors. Otherwise, check your gmail settings to ensure that you haven't blacklisted the address it's coming from, and make sure it's not being marked as spam.
If you used the same email address as the recipient (from to the same ), especially if instead of using gmail, you use your own domain that forwards to gmail. Did you try sending from one email address to a totally different email address?