It's normal for a stutter to fluctuate and when it does, it can create a feedback of look of anxiety, stress a tension. Look at your life and your worklife. Is there anything unusual going on? Anything stressful? Something as simple as a change in your usual routine. You've mentioned you're becoming more comfortable talking to people, WHICH IS GREAT. It also could be a momentarily "Oh no! Time to get anxious because we''re talking to people!" phase that your brain decided to go through. I've had days where my stutter is so bad that I'm out of breath. Usually, if I take a moment and reflect.. talk it through with co-workers or my boyfriend, we can identify an increase in stress. And it might be a REALLY minor increase but it's there. Give yourself a few hours or a day and take care of yourself. Do something relaxing, maybe spend a day with just yourself and your loved ones and let your voice (specifically your voice muscles and the voice part of your brain) to rest and relax and restart. Good luck!