S&T Intern Burnout - trying out AM?

Hey guys,

I'm looking for advice as I'm a bit lost on what to do with my life and don't wanna make the wrong choice.

I recently had the chance to get an S&T internship in a big bank in Europe after a lot of hard work - pretty successful and growing flow desk (they also hinted I'd get a job if I did good enough). The problem is that I was given a lot of responsibilities, basically the same as a fulltime employee and was struggling a lot with my work. I was working from 6:30am to 7:00pm everyday and felt like I was always too slow, not good enough, I was thinking about work all the time (at home, during my commute etc...).
I know this is nothing compared to what my friends in M&A do or what many of you are going through, it's just that I felt like I started hating work and that it wasn't what I wanted to do with my life. I went in this direction because it felt natural to find a good paying job in finance after my family sacrificed so much so I could get into a good school and find a good job (I'm a foreign student from a modest family).

Now, I started looking for another internship focusing on AM which I heard provided with a better work/life balance and got an interview for an internship in RFP.  Yet, I don't know what went through my mind when I still applied to another S&T position.
Do you guys have any advice? The S&T internship is in Credit Sales, I was wondering if it would maybe be less stressful than my previous position (flow).
I'm really lost because I don't know if I'm really not made for S&T or if it was just this particular desk in this particular bank. What about working in RFP? Is it just another middle office job in disguise? What I'm looking for in life is just a job that pays decently well (no need to be rich), isn't too boring and in which I would also have some work/life balance.
Thanks a lot guys, I know I look like an ungrateful retard, but when I started to consider throwing myself under the train every morning, I knew I had to do it.