Yes, I understand!
I seriously thought I was bipolar at one point. When I feel good, I do crazy-ish things and not care. I feel emotions, don't dwell on it, jump from place to place and feel pretty good, pat myself on the back for experiencing life, tasting life.
Then when I am in a bad/trampled mood, I mope, I dwell, I sleep all day, get all ... well you know ...
There are days when I wish I am NT and don't feel these things, but just feel passionate about ideas and inventions and non-human things. I'd like to say that it's better than feeling 'nothing', it's better than being dead. Like when I am happy, I feel very much like a child, I don't think I will ever lose that child-like sparkle and I don't mind that. I hate seeing adults all serious and grumpy all the time. I really take to people who are very energetic and happy.
But sometimes, it is hard. You don't know what you are going to feel tomorrow even as you try to control your feelings. It's this thing that's alive within you, something you can't control.
I am learning how to Te-lessen my Fi though and it is very, very helpful. Some things are just negative patterns or learned traits and these need not be kept to be hurtful to us again and again.