If you read my blog, you know that I don't think pursuing happiness is a good goal to have. Yet, that doesn't mean it's a good idea to be unhappy. While it's obviously normal to feel down at times, being unhappy for a prolonged time has seriously negative effects on your health, productivity and relationships. I don't think I have to prove that to you. Still, if you're struggling with chronic unhappiness, you might find it difficult to comply with "don't be unhappy".
I think that one of the largest problems in that regard is that there is a big misconception baked into our language. The words "happiness" and "unhappiness" suggest that the two are opposite ends of a spectrum. I would argue that, although the two are not uncorrelated, this is deceiving and unhelpful. It suggest that, in order to counter unhappiness, you should do things that will make you happy. But happiness is a much more fleeting sensation than unhappiness and, although the happiness will numb the feeling of unhappiness for a while, it will not get rid of it. In order to really address unhappiness, you have to get rid of what makes you unhappy.
What I observe from unhappy people I've talked to is that most people have absolutely no idea how to do that. If you ask them what makes them unhappy, they'll always name things that are completely outside their control and if you find ways how they might improve their situation they'll be impressively creative to come up with excuses why that wouldn't work. It seems almost like they want to be unhappy. Which might be closer to the truth than you think.
To understand this, let's look at situations where it's easy to fight unhappiness. Imagine you're really craving some ice cream, but you don't have any. The lack of ice cream makes you really unhappy. As a result, you decide to go and buy some ice cream. Done. You're not unhappy anymore because the reason to be unhappy has been eliminated. That is the simple mechanism behind unhappiness. Just like happiness is a mechanism you use to achieve your goals, unhappiness is a mechanism you use to resolve problems you encounter along the way.
Can you already guess what I'm getting at? Just like it makes no sense to see happiness as a goal, it makes no sense to see unhappiness as the problem. Just like you need to be in control of happiness, you need to be in control of unhappiness. And most importantly, achieving one does not automatically give you the other.
So, if you're unhappy about something, ask yourself if it actually makes sense to be unhappy about this. I've observed countless times how people suffer from being unhappy about things they have no business being unhappy about. What do I mean by this? Do I now try to prescribe what people can or cannot feel? No, obviously you're free to feel unhappy about whatever you want. It's just not very smart to feel unhappy about problems you're not committed to address, especially if there are easy ways to mitigate the direct effects the problem has on you.
I know that this is all easier said than done. You can't simply decide not to be unhappy. It takes a lot of negotiating with yourself. I'm not claiming that I've achieved perfect control about unhappiness myself. There's one particular unhappiness that it seems I just cannot resolve. For privacy reasons, I'm not going to tell you what it is. Just that I don't think there is a way for me to resolve it, there is no easy way to mitigate the effects it has on me, yet I also cannot convince myself to let go of the commitment to solve it, as that has been inscribed into my body by evolution. I'd love to get rid of this particular unhappiness and would be willing to give a lot for it (I wouldn't give everything, though).
But if you can't get rid of your unhappiness, the least you can do is try to keep it contained. Don't let it control you. Mitigate the negative effects it has on your life. Learn to live with it. And most importantly, don't get stuck in a feedback loop where you're unhappy that you're unhappy. I've fully accepted that I will carry this one particular unhappiness to the grave. That doesn't mean that my life has to suck. Neither does yours.
So, try not to be unhappy. And if that doesn't work, try to be happy instead.