Hi, Charlotte! I'm so glad that you came here to discuss your situation. There are many kind and supportive people here; and lots of people who have experiences similar to yours.

Like you, I was raised to keep any negative emotions to myself. I know the frustration of feeling that something is wrong, needing support and being unable to disclose to my family and friends that I even had a problem. (My counselor is struggling with me right now to get me to open up and be honest about my emotions.)

Charlotte, you definitely need to see a professional who can evaluate your situation and help you to cope with it. It's a very tough thing that you've lost your Mom, and I wonder if this is contributing to your sadness.

There should be a public health department in your area. If you cannot afford to pay for counseling services, they may be able to help you out.
Also, many areas have public mental health centers which serve their clients for little or no fee. I do think, though, that you should start with a trusted teacher, guidance counselor or other adult. One thing that they could do for you is to talk about this to your Dad for you and let him know that you need to be evaluated. If he hears this from another adult, particularly a teacher or guidance counselor, he's more likely to take it seriously and help you to find a good psychiatrist or therapist.

Please keep us posted on how things are going. People here really do care.