I won't lie to you.... physically, you're weak. Like triton, I'm
1.70m/63kg... though I don't have any plans to bulk up.
Anyway, just remember that physical weakness is not a true measure
of weakness, regardless of what people may tell you. I used to be
1.70m/53kg... and my dad always used to scold me and look down on
me for being weak whenever I got bullied.
You are only weak when you choose to listen to people who tell you
that physical weakness is something to be ashamed of. Physically,
yes, you're weak, but I don't look down on you for that. Besides,
you can always bulk up and go into strength training to be
physically stronger.
God bless.... and good luck. 
