And sometimes those are the days I have to stop mid training because I realize I am getting sick x_x

Definitely. A lot of times my brain feels run down after a long day of work and screens so I don’t want the mental load of going to the gym. Then I get there and feel so good halfway through my warm-ups.

For sure. The days i dread going are the ones i need it the most

It is opposite in my experience. I never hit my planned reps or new PRs on days I don’t feel like going to the gym