Is life just a constant string of rejection?

Guys.. Its a cruel world out there... Ive spent the last 10 years in sales and business development..Now im in design.. and have done alot of good work...Im starting to realize my entire life has been full of no's and you are not good enoughs... Despite knowing I could be really good, and have been very successful at 3 fortune 500 companies.. I've always gotten passed over for that promotion because my education wasn't good enough, ive constantly been told that my work isn't enough..or that its just too risky to take a chance on me.. Im always willing to make the changes..or give people the option to quit my services at any time.. But lately.. im finding myself really shut down.. Ive put in the max effort on just about everything I do...and just constantly get shut down... I always work to prove them wrong and eventually usually do..find a better client or a better job.. But after going through a large string of no's and you arent good enough for us people... Im starting to have trouble picking myself up by my bootstraps.. As that's happened, its sent me into this really deep depression where I realized I can maybe count on 1 hand the number of people that believed in me or gave me a shot (which all worked out to some extent).... Can anyone relate? Is life just a constant uphill battle of people telling you no/you aren't good enough?? Peppered with they VERY VERY rare occasion you might be given a shot...? Can anyone tell of a time they had this constant sting of rejections? If not any advice or experiences are much appreciated..