Don't take it too seriously. Taking a slow time too hard will only shorten your running life. As in almost every other area of life, the ability to laugh at yourself is invaluable. Set your goals a little lower. This is probably the toughest lesson of all to learn.
Runners are all about striving for the best.
Having to lower your sights is often difficult. The higher level performers have a particularly hard time with this, which is why world and national class runners often opt to give it all up rather than run slower, especially when they start finishing behind runners they used to regularly beat. Once you adjust to this reality however, you find it's ok to finish farther back in the pack. It may not be a PR, but breaking three will provide a great deal of satisfaction - when I do it again. This is a question each individual must decide for themselves.