can I be legally fired from my job for self harming and disclosing my suicidal thoughts?

Having a tough day and got caught self harming at work. When I asked why I told the lead I was having suicidal thoughts and some physical pain helped bring my depression back into a manageable place. Was told I could be fired for self harming and also got having suicidal thoughts/being depressed. Looked around on Google and couldn't find a sound definitive answer to the titles question. Help, please??