What can be the remedy here? Whenever I go for meditation retreat(self-exploration or in group), my brain remains calm, body remains healthy, digestive system becomes good. 

When I try to go for household life or even think about it, my tension increases, digestive system corrupts(whereas it remains better during retreat), can't maintain percept of not eating after midday  because of stomach. Morning workout (physical) makes me more lazy(sleepy), laziness decreases meditation. Metta-meditation makes me to worry about others whereas, if I don't do metta it, makes me feel like selfish? 

Should I consult psychologist or should I go for monk-life? 

How to stop worrying about others or why do I feel like worrying about others during metta?
Should I consult psychologist or should I go for monk-life?


If you are ready to be a monk and live by the Vinaya, by all mean do.

A householders life is not cut out for fasting for everyone. Even monks who are engaged in lot of activity find it difficult to fast afternoon. If you meditate for long hours fasting afternoon is not a problem, but when you get many worldly activities this becomes problematic.

I don't think this is something a psychologist can help but more to do with the amount or meditation you pratice.


  How to stop worrying about others or why do I feel like worrying about others during metta?


There are 4 Brahmavihara of which Metta is one. The objective of Metta meditation is to develop loving-kindness and benevolence and also break mental tendency to classify being as favourable and unfavourable hence reacting with craving and aversion.  

In your case, if you are developing worrying thoughts due to the concern for others or their situation, the best is that you concentrate on Upekkha and later develop the other Brahmaviharas.