This cannot wait until April! Your teen is sensitive, anxious, feels attacked, and feels that no one understands or supports her. And her dad sounds like he's pretty much substantiating that by just watching tv and telling her to quit "messing around". And you are trying to find her some professional help, which is the right thing to do, but you're trying to fit your daughter's needs in when your work schedule will permit it.
I get it - work is important and provides income and often health insurance. Most people can't just quit their jobs.
But your teen is in distress. Take time off, ask for a family medical leave, emergency leave, whatever. Take Diane B's advice about talking with your daughter's doctors, school counselors and your insurance company, and ask them for a suggestion. Spend a day making calls to psychologists, psychiatrists, therapists. Look them up on HealthGrades (a website) and find an appointment for your daughter.
And, on that day off, talk with her. Yes, it will probably be annoying. No, you can't "fix" the problems she's having by making cookies or just listening. But you can tell her "honey, I know you're unhappy and I'm listening. I love you and I'm here for you. I will be by your side and try to help you understand why you feel the way you do. It's not stupid, or silly. You have the right to feel like you do, but you know and I know that you're smart and kind and loved, and I want to find ways to help you feel happier, with others and with yourself."
Even if she doesn't respond with hugs and gratefulness, don't stop trying. Your daughter is sending important signals and they can't wait until April. Websites or books won't be the answer here. She needs help that only a human can provide: a doctor, a therapist, a counselor. She might need medication at some point. That's ok. If she were displaying signs of diabetes or had an infection, you wouldn't wait. Mental health and emotional security can't wait either.
My daughter sees a psychiatrist regularly, but I see consult a counselor too, in order to help me as a mother understand my challenging daughter. It has helped tremendously.