1. You don't open the third eye my friend. Something I came to learn personally. You balance what is already there. The chakras are already 'open'. You balance their frequencies by tunning into their purpose.
2. The thought and feeling that you lost your ability after a great ammount of success is the common obstacles we are have to overcome. Each and everyone of us here has been through that. You need to simply seek your inner strength and realize what you are capable of to find your true self and build the self confidence needed to keep going with these abilities. You never loose them. It's like saying that you lost your ability of your artistic expression. Whatever it is, it may seem like you lost the ability but it's another part of the learning process. To see how far you would go even in seemingly hopeless or lost situations. Don't give up.