Sometimes, things really just don't work out the way you want them to be.  It's fine. Just carry on.  If the chance comes by again for a positive opportunity, take it.  If the chance comes by again for an opportunity that ended negatively, think about things carefully, mull over it for a few days, talk about it with some people you know that care.  Then, and only then, can you decide whether to give the opportunity a second chance.