I started the job I'm currently at some months ago, and since then I've been pretty shitty. There are some days where I feel less shitty, I feel like I accomplished something, but at the end of the day, it feels shitty.

I had been here previously, and my gut had told me since then to quit, and it did the same again since I started working here again. I'm afraid I'm losing my time here, time that could be precious doing something else that would mean more to me.

They didn't keep up with some parts of the contract, I'm receiving pretty much nothing since I'm in a non-existent "formation", it's overall a whole load of crap.

I was supposed to do some stuff with Python, but then they told me to focus on Java and do some stuff after I was trying to learn (by myself) Python for a month, then they told me to do stuff with another completely different language again. WTF? I felt like I was shit.
Even in the last time I was working here, I was feeling the same, people were asking me to do webpages and other web things and then discarded them (literally) after I worked on them for weeks or they asked me to remake them COMPLETELY.
I had also been promised money for some side-jobs like doing websites for their friends, but in total I've received like 2/6 of what I was supposed to get.

Overall, I feel like my experience here has been shit, but I'm scared I won't find another job for these next 6 months (I'm taking a year off college to get some money)

If I follow my gut, my heart, and try to "fight" for my happiness, I'm leaving
If I follow my brain, and possibly become even more sad and miserable, I'm staying.
Who's the strongest?

I know you might even say "it's just some months" but those months will make a complete difference when I look backwards at my journey. I believe we cannot waste any time in life being unhappy.

Why couldn't they keep all their promises, not take advantage of me paying me so low... I'm completely sure I would receive more money somewhere else.

Well, I guess this rant is about my employer and the conflict between my gut and my brain.
Why can't y'all be friends and be on the same page?