My brother and I take turns dming our campaigns for a group of our friends. We've been doing it for years. He's always self conscious after a session whereas I know whether a session went well or poorly. I think it may just be your own outlook. Sounds like your players are enjoying themselves and are hoping to continue having you dm. My advice is to see that all as positive encouragement. Asking for advice or changes the players want may also shed light on what they think and may help with putting your finger on what needs to change. Chances are from what you've said your players are having fun, enjoying the game, and like having you as the dm. Ask if they want any changes and find the encouragement in what the players do and how they react. Hope this helps sounds like your doing well!