In this dream, it definitely sounds like the carnival is an emotional setting more than a direct symbol. I have to agree with Motts on the big interpretation. The being lost in the crowd and the being left behind by people in your life...

I'd add to this, there's a theme here about time running out. Some sort of deadline. This could be just the general sense of life passing you by, or there could be some actual deadline for whatever decision you haven't made being imminent. Also, the need to find the people you were at the carnival with seems important...

On the surface, this need to find people could be a clinging to those you care about in life, and not wanting to move forward without them. However, understand that you are the one describing your dream self as "stuck". There's a decision to make around letting these people go...

And that leads to the other bit when people are involved in the dream. Every character, present or implied, is a part of your own psyche. So we have to ask who couldn't you find? And why? These parts of your Self might be parts that are long gone. And if that's the case then the searching for them feels like nostalgia. But we can't cling to the past if we wish to move into the future.