Good for you that you're being aware of your surroundings ... because you need to be, we all need to be, because you never know what can happen in a situation like that.
However ... please don't let this bother you too much, simply because (and I've done this a lot) we often put ideas in our own heads about what people are talking about (us) because we're insecure about it. It gets worse when you dwell on it and you unconsciously convince yourself that they were positively talking about you when ... they (MOST LIKELY) weren't.
My mom gave me good advice about this awhile ago ... she said, "Andrea, don't be so into yourself. The whole world isn't watching you all the time ... get over it and focus on what you're doing, not what someone else is thinking." And you know, that's very true. At the early stages of transition, or even in general in transition, I think we get too caught up with our image and how we look for other people, we forget ... we're doing this for ourselves, not them ... and to tell you the truth ...
when you *stop* focusing on what others are thinking, you pass even better because your confidence comes through.Good luck with things hun