Being unhappy is part of being happy

The title may sound contradictory and probably it is.
Now that I have time to think in of other things than besides studying, I started to recapitulate(or review) my short life. If I had to summarized my life up until now, let´s I would have to say that it has almost been is almost a total success even though I have had to solve a lot of problems to solved during the process along the way.(in my opinion this just sounds better although you were correct) Don´t dare to think that it was an easy task. But (never begin a sentence in English with "but" or "and") is just In order to be almost a success, obviously something is missing or maybe more than one thing is missing. (this part is just redundant and not necesary to convey the meaning of the sentence)
Now, I realized that we are always are looking for the little things that make us happy. The happy feeling don´t last much so we are continously seeking for new things to be happy. (this sentence is basically just repeating what the previous sentence said) I want to be happy but also happy content (too many "happy's in this sentence) with my unhappiness too. I don´t want to try to hide the unhappiness of my life with happy things that only make you feel good for a short time. I think it is better to be conscious of the dark side of happiness, to accept it and even more, to treasure it. The more you know about yourself makes you a more secure and confident person. At least I hope it is so. I´m trying to be happy without search looking for it and accepting the unhappy things in life. In fact, I feel released of an emotional burden. Well, tell me if you agree or disagree with this. I will love to know your opinion.

I think that you can be very happy about this post!  Well written with just some relatively minor corrections and changes.  Obviously, you have a very good grasp of the English language as your choice of words and sentence structure shows us.  

One thing that I would recommend for future posts is that you break up your post using paragraphs, especially for longer ones like this.  It just makes it easier to read and lets us pause for a brief moment to digest the information the paragraph has given us before we continue.

Keep up your excellent work and I would very much enjoy to help you improve your English proficiency in return for some much needed help with my rather basic Spanish!