Well, from your description, I have to say that you may suffer crossed eyes. And crossed eyes are a kind of eye conditions called eye turns, strabismus. And when it occurs, it is hard for your eyes to focus on. Also, because of them, there are some other eyes problems, such as eyestrain, blurry vision. Also, double vision, and headaches may occur too. If your situation is serious, patches and corrective glasses will be effective. In my opinion, you need to go and see the eye doctor. By the way, injuries to the brain, such as with a stroke or head injury can lead to strabismus. Anyway, just be careful about it.
It probably means you have a squint, or strabismus in another word. Squint refers the misalignment of two eyes. One eye focuses on one object, while the other eye points at a different direction. Squint needs immediate treatment once it is found. For children before 8 years old, patching works effectively to treat squint. covering on the good eye, then the squint eye is forced to work, and the muscles are strongthened. For squint eye caused by vision problem, such as myopia, hyperopia or astigmatism, wearing suitable glasses would be a proper treatment to prevent it. Because uaully the cause of squint eye is the imbalance of muscles which control the movement of eyeball, botulinum toxin injection or a surgery to adjust the muscles can work too. Yet you have to visit an oculist and find out what caused your squint eye. I think the squint eye prevent people from good vision, even 3D movies, and it makes people look weird too. You should take action now!
I think when your eyes cross, it means you have lazy eyes. Because you are too lazy or too relaxed and donâ€™t focus on something too much, so when you focus on something ,you will have crossed eyes and this is very common. If you want to give up this habit, you should force yourself to focus no matter what the situation or what you are looking at. This is a gradual process and as long as you do it, it will be fine for you.