You're not alone, Staggers, and I'm sure plenty of people with personal experience will have stories to tell.
I would expect it to depend at least partly on which antidepressant you're taking. The older ones (things like amitriptyline and clomipramine) and mirtazipine are quite sedating and might make you slower and less bothered about training. They also cause weight gain. The more commonly used SSRI-type antidepressants are unlikely to detract from your ability to train. However, it's quite widely (though anecdotally) recognised that they blunt creativity, so there could be some connection there.
Glad you ARE still training!