Look at it this way:
You had $65. You now have $15. You could easily have kept playing the $10 limits as you had the skills to play them and the confidence, however at the $50 level you are playing against players who also regularly do well at the $10 and $5 tables.

I don't mean to berate you, but you have to know that when you win 2 SNGs in a row you're not the man. If you want to keep going up, play a $20 table, but KEY to winning money in poker in all aspects of the game is knowing when you're beat.