Some things are worth waiting for; although true love is all I can think of right now . . and even then, "mostly true love" can usually get you through the night and might become true love.
Being happy though? You should do that right away. You should take what you have in your life right now and be happy about it. It doesn't have to be AMAZING happy either. It can be small happys.
The important thing is not to create an attitude of "something in the future is going to make me happy." That future may never come or that thing you need to be happy may never happen. Perhaps it won't live up to your expectations.
Find something today, right now, that you can be happy about. Think nearer term and make that happiness happen.
Make today a good day . . starting now.