The Workout and Beyond

Hi, so I’m a trainer at the gym and my girlfriend came to one of my sessions the other day. It was supposed to be a typical workout but she had been hinting about some new things we could try together lately, something different from our usual play. We were alone in a private room with the mats, and after a couple warm-up exercises, she asked if I would tie her up for an hour while working on her strength training using resistance bands as makeshift restraints. She wanted to feel held back but still able to push herself through the routine. It was intense being both her trainer and her Dom at once. We ended up pushing the limits of what we’ve done before, with her struggling and enjoying it in equal measure. Afterward, she seemed pleased, yet I can't help feeling a bit guilty about crossing those lines even though everything is consensual. Am I just overthinking this or was it really that big a deal? Anyone else ever experience something similar?