OP says Winning makes you high, and losing makes you suicidal.
Welcome to Forex - Enjoy your time here
This is where strengthening your discipline comes in. Finding a 'middle ground' that you lock into by master control of your discipline and strengthening your will power.
Step outside the lines and you will feel these emotional extremes.
Like other people have said, we are only human - and this is always going to something we must deal with, and keep under control.