Hey I just read your profile, what do you mean swimming is gone. B.S. I'm flying over their and giving you lessons.
What you have to do is unload the heart and here is how:
1/The stoke WILL be the front crawl "WITH A PULL BOY". Mandatory, no exceptions. This eliminates those big blood and O2 users being the legs. The legs trail behind you in line with your body, heels close to the surface. Engage your core to prevent fish tailing. Fish tailing causes drag. Be Long and lean even if you are built like a bowling ball!
2/ You will use the front quadrant technique. Their will always be an outstretched front arm, you will face the bottom of the pool, you will rotate and lead with your hips gliding on your side. [Do not use your shoulders to rotate your body onto the side or you WILL get injured]. After the pulling hand accomplishes the catch, you will close your armpit, this allows the large back and shoulder muscles to propel you fwd. The pulling arm is guided towards the hip [promoting a high elbow] and the thumb should graze the "hip". Finish the stroke with the lead and trailing arms fully outstretched in opposite directions. Recovery phase : Drag the trailing arm with a high elbow fwd, point the elbow at the fwd end of the pool with fingers behind the elbow and fingers close to the water surface as the arm moves fwd. Once the elbow passes your head, the hand now leads the elbow as the arm moves fwd. Once the recovery hand is abeam the opposite arms elbow [REMEMBER THIER IS ALWAYS AN OUTSTRETCHED ARM THATS WHY IT'S CALLED FRONT QUADRANT] the hand with thumb down slices into the water to be the new out stretched arm. It is at this point that you do the hand switch. Do not pull until the hips have initiated the roll to the new gliding side.
3/ You will swim down hill [you will not drown]. Learn to breath in the bow wave. when you breath your ear will be on your shoulder and look a little aft at your recovering elbow as it moves fwd. Do not lift your head. This prevents your legs from dragging. You will breath bilateral or every 3rd stroke.
4/ Study total immersion [Ti] swimming on U-tube. Think, do I look pretty like a Ti coach. This technique is nothing more then the hand switch technique. I'm 5'7" and get across a 25 mtr pool in 18 long graceful strokes. My heart rate is lower then when I walk. This is the technique of long distance open water swimmers!
Swim quiet and do not splash. Swimming will give you peace and comfort. The water is a beautiful environment, hence look pretty when you are in it. The water is not meant to be disturbed. All your are doing is separating molecules and gliding thru them. To do this you do not need to beat the water into submission. You use Ti technique. When you finish, the pool surface should be pancake flat. Never leave evidence that you were their. Cool Eh!? You can do it!
Get wet and have fun!