Is it too late?

What do u do when you feel like you've tried everything and everything has failed? You feel like you've failed yourself and others and time is no longer on your side. You may have messed up totally and feel guilty of messes that you've made. Ruined trusts, shattered dreams is all you seem to experience. The question, for most, comes and says to you, IS IT TOO LATE? What do I do? Do you stay the course and keep the pace or come to the realization that I may just be beating a dead horse. You look at the mistakes you've made and at times feel like you never can start again. Where do I go from here? Can I start again?