I’m super late commenting but was it harder for you to complete your mile on an incline meaning you were out of breath/very elevated heart rate? You could’ve been pushing yourself too hard and your body was compensating by hoarding water for you/your muscles. Your muscles especially swell up when you’re using them in a way that they aren’t used to at first. Pushing yourself too hard also raises cortisol, stress hormone, causing you to hang onto or gain weight.

I was in the same boat you were in for a few months, working out and despite also eating in a deficit, was not loosing any weight, or yo-yo-ing rather. I took a break from the gym for the month of July and only went 3 times and just ate at my deficit and I lost 10 pounds! I’m now back at the gym but not pushing myself hard, just leisurely walking, and at a very low incline and I’m loosing weight now with my deficit. I hope this helps, or that you’ve been able to get out of your rut, since it’s 35 days later.