This is why I hate DMing: I have to improvise multiple characters when I might have trouble getting into only one.
I had this feeling many times. And turns out I was at least partially wrong. My DMs then my players all told me I did a good-to-great job at some point. But myself I felt awful.
Not sure I will have it clear on mobile and in English but I’ll try. You are the only one to see your own mental backstage: your stress, your hesitations, your initial plot falling apart. The other players may have some guesses but usually they do not notice.
If you are not sure, ask them. And be sure you’ll only get better with time, more experienced, faster to come up with new ideas.
Now, I need to go back to work. If someone needs yo talk about it, I will find some free time with pleasure. But please don’t let those thingd hold you back from playing. Go there, be awkward and enjoy your game with your friends!