system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How can I suddenly become lonely?

I am generally absolutely fine with being alone, in fact at times I revel in it. However, for some reason at random intervals for approximately 5-6 hours at a time I feel near cripplingly lonely and for no apparent reason crave another person.

Is it a chemical situation or is it possible that I repress the feelings and they are always present without me noticing?
gpt
“Loneliness does not come from having no people about one, but from being unable to communicate the things that seem important to oneself, or from holding certain views which others find inadmissible.” 
― C.G. Jung

I don't believe there is chemical imbalance that leads to the specific emotion of loneliness. And, even introverts need interaction.