If you live in the now, there’s a good chance your heart controls your thought process. You don’t have time to think with your brain, you need an answer now so you use your heart to make decisions and thought process.
You're living in the now and letting your heart control all your thoughts. Why are you following your heart? You found you only have one 年 (ねん) to live, so you have to live for the now.
Currently there are no similar looking kanji which exist in the WaniKani learning system