Why do i seem to get tearful wanting to cry if i treat my self i've always felt this way.?

This may not seem serious question to other but i want to know have other ever felt this way even seeing other have fun while i feel needing have my quite moment not wanting other to see me looking teary eyed at another thing I have just brought that i have been saving a few years to save for a descent car then have finance or loans may be when it comes to purchasing a car properly i just cry buckets at what i've achieved at going without for so long.