I would be very tempted to reach for something if I had that kind of day every day too. I'm not going to talk about what you're eating or your gym because I don't think that's the biggest problem.
You need to breathe. Stop the negative thoughts. Stop hating yourself. Live in each moment and stop worrying about whether or not your life is living up to your expectations. Others here will recommend therapy. Many people have found it useful, but not me. I just needed to reinvent my outlook on life.
I work full time and I am a full time grad student in thesis. I spend four hours commuting each day. I get up at 4:45am every morning, leave the house at 5:30 and don't return until about 6pm. I work toward happiness. I ignore the things that give me the impression that I need to change myself. I stop and smell flowers (literally!) while walking to the bus station. I take each moment as an opportunity to experience the world, even though it's never 100% pleasant (it's never 100% bad, either).
You are worthy of happiness. You are capable of happiness (right here! right now!). You just need to claim it.
"Things are as they are. Looking out into it the universe at night, we make no comparisons between right and wrong stars, nor between well and badly arranged constellations." - Alan Watts