I can relate. I am 40 and I have been working two jobs since October 2016 -totaling to about 70 hours/week- and I have to continue to do so for another year or so. I have not taken more than a three day vacation since I was 18. I am very exhausted.
I very much agree with you. One must work hard in her/his 20s into early 30s.... but now I am burned out and I want to give up but I cannot.
I hope your situation will be short lived and you will soon find a full-time job that will provide a decent pay and a stress free living.