Look after yourself. You deserve more than heart ache and struggles. You deserve to smile more than "once in a while". You're better than that.
Love yourself. (But not too much: that's a sin, so they say.) Remember, though, that other people love you, too. Even if they don't say it.
Look after others. It's hard, I know. They might not want to let you. You might not realise who needs you. You might feel overwhelmed by them. None of that matters.
Be happy. Not just for yourself ("Your health is your wealth") but for other people. Smile. It's infectious.
Talk to people. Talk to friends about everything happening in your life, the good and the bad. Talk about nothing in particular. Talk to strangers. But:
Listen. Everyone has something to say. Keep talking and they won't get a chance.
And always remember what's important to you. When you say "I love you", mean it. When you care about someone or something, show it. When you believe in something, do something about it.
Never forget that you matter.