Well... don't be too hard on yourself.
And 1000 meters? Start smaller!
How about asking what we swim a 100 in? Or a 50?
I will say that I swim 100 yards in 1:30 in a pool... and I can swim 1.2 miles in 40 minutes in a lake.
AND... I use to be a competitive swimmer... so I have a really solid stroke. Swimming is effortless for me.
Running is the area I have trouble with! And a race isn't won on the swim... it's won on the bike or the run!
So... do what you can... you will get faster. Don't worry what others are doing... swim your swim.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"