What is your BMI?
How is your health?
What do you eat? 3x daily?
How frequent do you fap?
What are common activities do you do?

What type of food do you usually eat?
What age group are you?

Understand you are shy. To the point, reduce masturbation.

Congratulations, you should qualify to be a blood donor.
If you continue to eat like that, you should hit the peak of your BMI by 30s
Even with regular exercise.

Are you a smoker/ vapper?

To donate blood, minimum weight is 45kg, good health, enough sleep and other requirements.

If you have discomfort then see doctor at the same time ask about worms inside digestive system.
After doctor diagnose, if necessary there are de-worming prescription you can take.

Also person in good health with good lifestyle and eating would not gaining excessive weight either. Maybe you are normal.