You're not alone. Mental illnesses affects millions of people worldwide, many too scared to say anything about what they're feeling because of the stigma around it. Getting help is not a "privilege" that only some people deserve, everyone deserves to have their mental illness taken as seriously as it should be.
Just because you can't see it, doesn't mean it's not there. You are not an outcast, a freak, abnormal, you are human. Your mental illness does not define you although it is a part of you. If people can't see past your mental illness to who you are, they don't deserve to have anything to do with you. Your mental illness is 100% valid.
Although tumblr can't diagnose you, if you haven't been "officially diagnosed" that doesn't mean you suffer any less. Many go through their lives not wanting to seek the help they need. Labels are horrible things. To finally be told what is actually going on in your brain is a scary thing, it's okay to not want that. Alternatively it is fine to want a label, to know what is going on, to want to be able to handle your mental illness by knowing what exactly it is.
Talking to people isn't a bad thing. Find someone who will understand you, there will be people who will understand, I promise. If you can't talk to people in your physical life, social media can be a great asset. Many people (like myself) and so so so happy with talking to people about their problems. We want to help if you want us to.
If you go to counselling/therapy/other, the person that you see does not know how you feel unless you tell them. Listen to their advice because from experience I know that not listening is the worst thing. For example with my depression, my counsellor told me that I still needed to see her and I was just having a good couple of days/weeks/months and without medial help I would slip back into old habits. I didn't listen and they were so unexplainable right.
Not wanting to tell your parents is normal. Being scared of people finding out is normal.
Wanting to tell your parents but not knowing how is normal.
Being open about your mental illness is normal.
People with mental illnesses are seen as not normal. We are people. Just because of the chemical imbalance in my brain, it doesn't mean that I am not worthy of love.
It is normal to not want medication for your mental illness because you don't know who you are without your mental illness. If you want medication, go for it. If you don't, you don't have to have it.
People deal with things differently. Just because people don't deal with things the way that you would, doesn't make them weak.
Self harm does not make you weak
Eating disorders do not make you weak
Mental illnesses do not make you weakYou are valid