i often end up crying during zazen. i’ve done it for a couple of years. i was never really sure why. it was just a thing. i cried for 5 mins after about 20 mins and then just got back on with the last 5 mins.
i (eventually) sat with an online group and they talked after sitting once about how zazen and zen aren’t there to deal with mental health issues. that’s what doctors, therapy etc are for. i had been definitely trying to “fix” some stuff that can’t be fixed through the practice for a while there.
this is why having a group or a teacher to practice with is important. i can get stuck in believing my own “crap” because i can’t see outside my own “crap”.
then again, sometimes “crap” zazen is just “crap” zazen. but having a group or a teacher helps with it — at least you’ll know you’re not the only one struggling! xD
As a concrete example, Shinzen Young says that he wouldn't trade a day of his life now, after lots of meditation, for a year before he started meditating, but also he didn't manage to deal with his procrastination through meditation and used psychotherapy here.
Another example of "not everything has to be dealt on during meditation", regular exercise, eating well, acting in a more honest/moral way (whatever those mean to you) all help meditation.