I’ve looked into the Senior Managers Regime and I don’t feel comfortable with having to comply with it. What does that mean for my future at my firm?

Your discomfort is not surprising. If your firm is regulated by the PRA and FCA and you are in what is deemed a senior management function, it is not a matter of choice - you will be caught by the new regime, which will entail a significant step up in scrutiny, personal accountability and responsibility of senior managers from the current approved persons regime.