I'm sorry you got a rejection letter the next day for a job interview that you thought went well. That happens to me a lot too and it's incredibly disheartening. You just can't let it discourage you. It might be that your interview went really well and you had all of the characteristics they were looking for even, but that there was someone else more qualified, with a longer work history, or who got hired internally, or who knew someone at the company or even the interviewer...There are so, so many factors.

I have some gaps in my work history currently due to struggling with mental illness and addiction issues for the past couple years. Obviously I don't want to tell my employers about the addiction issues, at the very least. I have been telling some employers that I was living with my boyfriend, who was in the military...Since I live close to an Air Force Base and I am relatively young, nobody really questions this story, even though it's not true. I have also said taking time off to care for sick family members. I have stretched the time I spent employed at jobs on applications, too, although I feel guilty doing this...

I don't know if any of that is helpful advice, but I just wanted to comment that you're not alone and I - and probably a lot of us - we're all in the same boat. Good luck and keep trying! I think volunteering is a great idea in the meantime, because you can always find those opportunities and then add them on your resume, and I think I will look into that myself.