It's highly unlikely you are pregnant, though do be careful for next time. It's not a good habit to start doing. And yes, it can move your period back if this is some of the first sexual activities you are doing. It can cause your hormones to fluctuate if that was the first time you "got off" by that sexual activity. Also stress will make your period late, too.
It's good to ask, so pat yourself on the back for that!
It is extremely unlikely you could be pregnant from the activity you describe. Also, fingering will not change when your period happens. Stress, diet, all kinds of things can mess with your cycle.