You might just be late and stressing about it will result in the period being even more delayed. Relax. You were protected and you were quite conscious. Periods are often late due to various reasons.
Anna --
The sticky, egg white-like substance you found in your panties are signs of ovulation. You may see this every month about roughly 2-weeks before your period arrives. It's great that you used a condom and that you didn't find any evidence of breakage! That being said, you should be fine (aka not pregnant) and should just wait for your period to come on its own. If you stress yourself out enough it WILL delay your period.