My dad is making me depressed!

Hi, I am 22 years old and in need of help. I live on my own but have to get help from my parents to make ends meet. I work as much as possible but I only have one part time job right now. I have been trying for the past year to get a full time job or another part time job, but no one will hire me. My mother is very very stingy with giving me money and normally I have to loan it from her. Which would be fine if she actually gave me enough to make my ends meet. My father is on fixed income so I hate the idea of taking money from him, but he is always asking me if I need money, and I can't lie to him. The problem started a few years ago. My dad was diagnosed with having a failing liver. When I heard this I became so extremely depressed that I found whatever outlet would take my mind off of it. That outlet was gambling. I spent all my savings, my stock, and then I moved on to his money. I have been trying like hell to pay him back but something is always coming up. He has been on a steady spiral of clinical depression for the past several years but he also has some normal days. When it comes time for my rent to be due, I am usually a little short. He gives me some money then I pay him back within a week or two. But this month was different. I am taking a trip for spring break to south padre. I was misled about some of the payment information so I had to borrow a couple hundred dollars from him to pay my rent. He instantly started yelling at me about how I never pay him back and something always comes up. I knew he was in a foul mood so I didn't argue with him I just left because I had already explained to him that I would pay him back what I had to borrow plus some in march when my pell grant comes through. Am I being greedy or irrational? I would like to think that I am doing the best I can. I know that this trip is probably not the best idea financially, but I see it as a once in a lifetime opportunity. I know that when I see him again his mood will probably have changed, but it doesn't change the way I feel now. I can't stand the thought of him being upset with me I love him and it just kills me inside. Any thoughts or advice?