I recieved an email saying that I am approaching or over my resource limit. What does this mean?

This means that you are nearing the capacity of your QWK.net web hosting account.  The email you received will specify exactly what resource is over the web hosting account limit. 

Possibilities include traffic, disk usage, mysql database, or even a specific email account.  If the resource limit notification refers to traffic or disk usage, it may be time to upgrade your QWK.net web hosting account. 

If the resource limit is dealing with a single email account, you can either delete excess emails or increase the email account capacity which may result in additional cost.  Check to see if an account upgrade is more economical.