Throttling - Too many connections - Manual reset?

My website (running 4.3.2 and xtemplate) all of a sudden got the "Too many connections" error. Checking server stats I see that the website is getting its normal traffic...the same kind of traffic it always gets...which about about 500 views a day. The website has not been reachable since early this morning.

What do I need to do to get my website functioning as normal and how do I do it? Is there a way of manually resetting "something" on the server or do I have to wait this one out?

Thank you very much in advance,
-Eric

PS: I can remember last night seeing that there were about 150 visitors on the site via the "Who's Online Block". I normally do not pay much attention to that block and I don't recall seeing that number of visitors that large, but it would not be hard for me to believe that upon each website visit a new session starts and does not end. Perhap Drupal and my database thinks that a large number of visitors are hitting the site, when in fact all of the sessions never cleared. The site is about 4 weeks old and doesn't get much traffic at all. Thanks again.