Depends on how he is making you sad and cry. I don't think it's worth it for you to be around someone that makes you cry all the time. If he's hurting you, then it's time to get away from him and find someone who really cares about you as it seems to me that anyone who constantly hurts you isn't worth it.
He makes me happy but at the same time so sad that I'm crying myself to sleep tonight. Is he worth it?
Well THAT would depend on just how happy and how sad he makes you .. And how often.
Understand that there are times when every couple has a disagreement, or things are not 'so great' as they would normally be .. THAT doesn't mean he isn't worth it ... that may very well mean your relationship is 'normal'.
If you want to know if HE is worth it .. Don't just take an inventory of his behaviour and characterists .. Take inventory of you both as a couple. THAT is how you can decide .. Its not about if HE is a good person, but if you both are a good match.
How can you be so emotionally involved with someone that you've never met? I can't understand that at all. You're not in a relationship with him, he's an unknown figure on the internet. Try a face to face relationship with someone else, in the flesh.