Everybody has doubts. The question is what to do with them. John the Immersor did the correct thing.
And John, calling two of his disciples to him, sent them to the Lord, saying, “Are you the one who is to come, or shall we look for another?”
Luke 7:18b-19 ESV
Jesus answers doubt. He resolves our doubts. His reply to John was decisive and complete. There is no doubt that he cannot deal with.
Perhaps his reply is not what we want to hear. But that raises another issue, if we will accept him as Lord or not. It is not by chance that John sent to question the "Lord."/1
So what's your doubt?
1/ I'm not unaware of the textual difficulty in the verse, with the manuscripts divided between the readings "Jesus" and "the Lord." See the NET Bible note for a tendency to favor the former reading.