If you are going trough hard times or you are dealing with just the usual discomfort of life, it can be overwhelming to deal with all of your emotions sometimes.
Your emotions come in waves, because we live in a bipolar world energy flows from one pole to the other. Finding emotional balance simply means flowing from one negative to positive.
People who have a hard time in usual with negative emotions, it is because they rejected the negative aspects of life so this stifle the emotional flow. Think of it like this, most people find the sound of the ocean waves pleasant and relaxing, if somehow you could convince someone that every time a wave reaches the shore a dolphin dies, if you like dolphins listening to the ocean waves is going to become a horrible experience.
Our bodies have the capacity to transform pain in too pleasure and pleasure in too pain through the endocrine system by secreting a class of hormones called endorphin's. There are two cases in which these hormones are being secreted, the first case is to serve as reinforcement for good behavior, the second reason is to stop pain. The same way exogenous morphine is used as an anesthetic in medicine, you can subject someone to very painful procedures under the effects of theses drugs that person won't feel a thing.
This is why pain always leads to pleasure and pleasure to pain, nobody is fully stuck in any of the extremes, however some people tend to be more predominantly in one extreme over the other. I never heard anybody complaining about being to positive, it is really a problem when you become predominantly negative.
If opposites attract in order to move from positive to negative, you have to first accept the negativity that you already have in your life.
Sometimes the pain is too intense and horrible to be accepted, if this is the case you have to expose yourself in a controlled gradual way, like this your energy is going to flow and change. We are constantly suppressing some degree of pain, suppression it is a normal mechanism of your mind that is allowing you to don't be to distracted by your pain in order to keep you functional.
Pretty much at any point if you get ride of all your distractions, you will find pain underneath unless you have any special reason to be happy. If you put your attention on that pain for at least a second, the pain will eventually become unbearable and you will retreat in your distractions, after a while you can do the same thing stop all your distractions and place your attention on the pain for a second. If you repeat this process for as long as it is necessary you will eventually get relief from your pain.