I have contacted my host and they say the server is fine and said it was vbulletin.
It's not, it never is. That is total crap these call center mop swingers and burger flippers read from a script and have zero idea what they're talking about. Remember, with most any host the script is "blame the customer first."
WebPageTest is the best tool to use to diagnose issues. It is real world browsers on real world connections that don't cache and give you a real picture of what is going on. It is 100% objective and scientific - unlike most other "performance testers" out there, WPT isn't trying to sell you anything. Here is a test I ran on you:
The server is not responding. First byte time is 15 seconds then total load time is only a second more. This is THEM, not you. I see this all the time, on oversold shared hosting machines, and machines with software issues.
You're loading only 450kb which shouldn't take long to load at all. However, 300kb of that is your header image. It's linked to and listed as a jpg but it's not, it is a very fat PNG.
I have optimized this image for you, downloadable here. It's only 52kb now. Saving you about 250kb of unnecessary bloat. Upload this to your server in the /images/misc folder.