Made a big change, would appreciate feedback

Just for context, I started swimming five years ago and I'm 42 years old. After a lot of floundering I got down to 1:50 per 100, and I do about 3000 meters a workout. I used to just swim it out, now I'm working on intervals and actually trying to push myself in a semi intelligent way. I am haunted by my kicking problems, inasmuch as they're weaker than my arms and I tend to always move from side to side. I came to the conclusion this morning in my workout that breathing on only one side on every second stroke was forcing me to angle out every stroke and compounded my problems with keeping straight and letting my kicking propel me forward as opposed to side to side. I started working this morning on breathing on alternate sides on every third stroke and while I have to re-train my lungs to accept the breathing differently and get comfortable one goggling the non dominant side, I immediately saw a big change in how I was gliding through the water and felt like I was swimming a bit with a pull buoy. I had back surgery two years ago and for 18 months only swam with a buoy which probably made my problems a lot worse because I wasn't working on my core but was getting stronger with my pull, and wasn't addressing my weak kicking problem and facing up to the challenge of breathing on one side was pulling me a bit askance every stroke. Anyways here's the question for you pros. Am I thinking about this problem right? I tried to post the workout I need today. When I was working half through on breathing side to side I felt I had to go a lot slower to accommodate the new breathing technique and get comfortable with turning to the left, as well. Any feedback would be really helpful. I know it's going to take a long time to put the breathing, catch and kicking pieces back together but I really want to get down into the 1:30's per 100 just for me, and I know without some great kicking I will never ever get there.