Loneliness can be normal, and is only an indicator of underlying disease when feelings become excessive, all-consuming and interfere with daily living.
Islam doesn’t encourage loneliness as it leads to Shaytan been the companion of the person. Therefore, Islam encourages us to be in 3’s and above to avoid evil thoughts.
“Islam began as something strange and will revert to being strange as it began, so give glad tidings to the strangers.”
-The Prophet Muhammad ﷺ (Muslim)
This is a major problem in the convert community. We are lonely. The best thing we can do to fight the feeling of loneliness is to spend as much time as possible with good company. Having dinners with people a few nights a week is a sure way to maintain a good attitude. The practice of becoming a nun or a monk is alien to Islam; we are social creatures and Islam recognizes this.
Try not to lock yourself away in your apartment to avoid the world. This will just cause a vicious cycle that will cause deep depression and can lead to searching for solace in haram (unlawful).
Make it an obligation on yourself to remain a sociable human being. It takes a lot of work but the result is happiness and contentment in life.