The exhaustion is a sign you may be overtraining or overreaching. You are lifting 3x a week, you are running 3x a week and you are swimming 2 or 3x a week too. I was doing the Starting Strength lifting program (more or less) and got overtrained and exhausted on 3x a week of that plus one hike a week. I had to cut back. Lifting takes a lot more out of you than it seems it does. You have to eat a lot if you are going to keep your heart rate up like that all the time, too, even sacrificing weight loss to prevent burning out.
Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Current squat: 157.5 x 2