So, if my shared hosting site is attacked and my site slows to a crawl, does that mean EVERY site on the server is slowed, or just my site specifically on the server?? If it slows that much, what is being used up? Do hosts disable their customers for these attacks? I'm only paying $15 a month!

thanks for the help

sounds good.

A ddos is a distributed attack, which means than thousands of requests per seconds coming from thousands of different computers are hitting a site your hoster have on the same server as yours.

There are not much to counter that, except than disabling the DNS record, which can take some times, and could be inneficace if the ddos is directed to a IP adress (in which case, an remapping of the server adress can be done).

The hosting center can try to find a common pattern in the request, and filter valid requests and invalid requests, but it will only prevent the request from accessing the server.
And numerous "valid" request from usual customers / visitors might be tackled as being part of the DDOS.

Appart from the server load getting higher with the more connections, the bandwith used by the request coming to the hosting center will still be used, even if the requests are discarded before hitting the server.

So, there is not much to be done.
You can only wait, or if you are not the target of the ddos, try to move your site elsewhere and update your dns's