'I am agreeable' sounds very official - could that be 'I am willing to'?
For the last sentence, do you need the comma?
With a comma, it becomes almost an explanation of the previous sentence (for example: I do believe you. At least, most of what you say); without a comma, it seems to make more sense ( 'whatever else happened, at least I had a life' )
"Have it your own way" is an idiom and means to accept an action someone want to do. In Turkish "nasıl istersen öyle yap/nasıl mutlu oluyorsan öyle yap/kafana göre takıl/sen bilirsin and all".
"Do what you want to be happy" means to do the things that makes you happy.
But that specificity is added by the second sentence. It would be very difficult to interpret 'have it your own way' in THIS text referring to anything else than 'be happy'.
Thanks all - I'll accept