You did not introduce oxygen to your beer, you released CO2 from it, thats why you are seeing activity.
If you are not dry hopping, leave it in the primary for at least 3 weeks. It will clear properly.
What you are tasting is green beer and a world away from what you will get after it has been bottled and given enough time to adequately condition. The thin body will change and the hops will mellow.
I have a house IPA that tastes completely different each week it is in the bottle until about week 4 when it settles in to its flavor. I, too, was worried the first time I made it, but patience is the key.
By the way, for you and any other new brewer who reads this: No beer you make is adequately represented in a fermentor sample. Do not under ANY cicrumstances attempt to correct flavor or body at this stage. Give it at least 3 weeks in the fermentor and at least 3 weeks in the bottle before you judge. If you need to make adjustments you'll know for the next batch. PATIENCE.