To put it another way: 

How can I tell if a coworker/supervisor is saying "You're legitimately a good employee, but here's a couple way to get even better" or "You're subpar and need to improve in these ways or else you deserve to be fired"?

I recently started working entry level in special needs childcare, a field that I want to spend the rest of my career in, and I legitimately love what I do.I also like where I work- it's a small company and everyone's friendly and helpful with each other. But every week or so I get someone telling me that I did X thing wrong, or I need to do Y thing better. While I would MUCH rather hear criticism so I can fix what I'm doing,  as opposed to keep messing up even further, I don't know where I stand in everyone's eyes. Today I teared up and almost cried multiple times because I felt like an incompetent liability that's only bringing everyone around me down, just because my supervisor called me into her office and gave me some tips on how to handle a certain situation.

Should I be blunt and ask directly? Should I ask my coworkers if they get criticism as much as I do? Should I try being overly paranoid about making mistakes in order to keep them from happening?