Start a spreadsheet to track your winnings and losses. OR get some tracking software to do that for you. That way you can have more concrete results to pick apart.

But for SNG's, as I remember, the best indicator of what your asking is called ROI (Return On Investment). Here's a little thread about it. Check post 4 And 11 for quick answers, but read the whole thread.

1. I'd say 5-10% ROI should be considered a good return if you heavily multi-table (>10) and around 10-15% if you play less tables and get to pay attention and spot smaller edges . You can also track your own results on Sharkscope or PokerProLabs

2. You definitely need to change your style and adjust once you move up . On the lower limits you can make a good return just by taking them to value town but starting at the 10's you'll start to see familiar faces (regulars) and the mind games begin .

Also , just from 15 games you can't really tell much as you can run good or bad on a much larger sample. If you need help with specific hand open a thread in SNG & MTT Hand Analysis

15 games are nothing, really... play at least 100-200 games on this level(more is better).
-0%-5% You sligthly beat the limit
-If you have 5%-10% ROI It's good
-10%-15% Really good
-15%- Just awesome

Try out sharkscope. 5 searches are free/day and you can check your overallROI
Put notes on your enemies also.
gl!