Dand Theta, I wish I was 65kg. I'm only 49.5, I need to gain some weight :X
i started training 2nd of january 2010 as a "new years intent". i used to be very skinny all the way through school weighting about 62 KG at 1,79metres. and now after more than a year of fitness-training and eating stuff like i never did in my whole live (good stuff, no fast food) im weighting 74 KG.
so sign up in a fitness studio - its definately worth it!
65 KG? and 49.5 KG. - how tall are you and how old? when you get older you will also become heavier.
and everybody has moments when they are not in their best physically condition, so dont break your mind to much about it.