You have been noticing your network connection inexplicably going off and on for some time now, maybe a couple of months, but not to the point of becoming a big problem.
However, this week, the intermittence has escalated. You want to end this nuisance once and for all; for that, write a methodical plan delineating the actions to take.
Related posts:
Try replacing the Cat 5 wire first. Sometimes they begin to lose their usefullness.
If you are talking about a wireless ethernet connection, and you are using WEP encryption, it’s possible that your signal is being hacked. Google “hack WEP encryption” and you will learn that one of the techniques for breaking in causes your wireless connection to drop and restore frequently.