HIPAA (known in simpler terms as the 'privacy laws') prohibits anyone who works in any sort of healthcare environment from discussing patients, or even disclosing that you've been in their facility. It doesn't matter how familiar a healthcare worker may be to you individually.

I have a good friend and former co-worker who's also bipolar, but right now we don't talk about our meds or therapy sessions. We don't even discuss the fact that we're both patients in the same clinic, because he's an occupational therapist at the skilled nursing facility where my sister is, and thus we have a 'working' relationship again. So there should be no reason for that medical assistant to say anything even if she does make the connection.

There is a lot to be stressed out about in our world, but one's medical visits and privacy regarding them shouldn't be one of those stressors. There are serious consequences for breaching patient confidentiality and I'm sure she's aware of them. Try not to worry too much, 'K?