I can’t decide (mental problems)

so i’ve had some mental problems for over 4+- years and some trauma incidents and my brain and heart can’t really handle this. The problem is that i when i want people to listen to mw i start screaming really laud and making conflicts and bc of that i have problems with my pulse so i have it in my normal days like 110 but the norm is 60. My parents saying that im going crazy and not mentally stable and i have to go to psychiatrist. The problem is that around one year ago i was going a little bit crazy and saying to my parents that i have to get some help, they said that im just imagining and those doctors are scam and not going to help me with nothing.
So i left the thought of getting helped and that why year later i have serious heart, pulse problems.
The main problem is that if im gonna get diagnosed im not gonna receive one treatment that i wanted and don’t see sense in my life without so if IM gonna get diagnosed with some mental illness im WILL NOT receive that treatment, im a teen and my mental state can get worse with the treatment i want and without diagnosis (and probably some pills after)
What should i do?? i cant just refuse the treatment im getting on now, i waited for it 3 years i’ve never been so happy in my life when i got subscribed with it.
Help me?