The military caused my mental health to go from normal to unstable

I used to be happy and not care so much about every little thing, so many things in the last 2 years changed this for me. I joined the military and before that I wasn't so anxiety ridden or angry, and I haven't even left the country ever. I have no ptsd or seen horrible things, I've just become over stressed, angry and anxiety ridden. I'm seeking help but I'm still waiting for it to work, the simplest thing like me stubbing a toe anything that causes pain will make me break down, I start thinking of "this hurts" to a complete break down where I'm ugly crying and thinking about my life and the things I wish were one way or the things I don't like or the things that I feel responsible for. Why does this keep happening to me? I am still in btw and have a few more years until I'm out