Yes, you are being overly sensitive. My only suggestion is to talk to your coach and ask his/her opinion on where you belong. I can't imagine anyone getting bent out of shape by you moving up.
As we frequently say, it's just Masters swimming, feel the love.
I also see you live in Austin. This does change my tune a little bit. gull could be in the pool at the same time as you. He's notoriously mean and requires his own lane. Bribe him with coffee or just taser him, either works.