What does 'main thing' mean here? Is this something you would say to someone you care about?

Please help me interpret this - I have Aspergers and can't.

"Glad to hear that you're better today. But dont worry about what messages you sent and how people feel about that, if youre feeling better that's the main thing, and finding a good way to manage your stress, are there people at the uni who you can go talk to if you get yourself too stressed? I remember how stressful it could be at uni, especially at this point in the year when the focus is always on exams and assessments. But even those are not worth stressing so much about. Make sure to spend some time taking care of yourself and doing things you enjoy - there's more important things than grades!"

Is this somethings you would say to someone you care about?