Camlo - try not to compare yourself to others as you don't know their story. Yeah, she was pregnant and using your words she trounced you, but is she training for a 3.8k swim. Could she have kept her pace up for over an hour. Did she have perfect technique.. Was she going to hop on a bike for 112 miles and then run a marathon?
Spend some time watching others swim and you'll see that although they may be faster than you some elements of their technique could be poorer eg over rotate, windmill arms, too little or too much kicking etc etc
The only person you have to worry about is you; try to shut out what everyone else is doing because they, more than likely, have different aims and ambitions to you and so it is fruitless to make comparisons