Perplexity.ai:

Neurotic is an informal word for someone who tends to worry a lot, overthink, feel anxious or self-doubting, and react strongly to stress.

For example: if a person sends a text and then spends hours worrying that it sounded wrong, imagining the worst, they might jokingly call themselves “neurotic.”

A more accurate way to say it

In psychology, the related word is neuroticism: a personality trait describing how easily and intensely someone experiences difficult emotions such as worry, irritability, fear, or sadness—especially under stress. It is a spectrum, not an all-or-nothing label.

Important nuance

“Neurotic” can sound judgmental or insulting when used about another person. It also is not a formal diagnosis. If you mean someone is struggling, plainer and kinder language is usually better, such as:

• “They seem very anxious.”
• “They are under a lot of stress.”
• “They tend to overthink things.”
• “They seem especially sensitive to criticism or uncertainty.”

Everyone worries sometimes; the difference is how frequent, intense, and disruptive it becomes.