Giving up on working out

I went on vacation for a week, that being said I didn’t workout or really watch what I ate. Today is my first day of working out and I can’t complete the workout for the life of me.

I used to cycle for an hour and now I could barely hang on for 20 minutes. I tried to compensate by doing HITT for at least 20 minutes and I only completed it for 7 minutes. I feel like a failure 😞 how do I overcome this