Hi.
I've gone through your query. I can understand your anxiety. 
Your symptoms are due to 
Chronic Constipation or Faecal Impaction . I advice you to follow this, 
1. High dietary fibre intake : Oatmeal porridge, Chapatis, brown bread with butter, honey or fruits such as prunes, dates,figs,mangoes,apricots,Green vegetables. 
2. Drink 10 glasses of water in a day.
3. As you have tried enema & milk of 
magnesium, I suggest you to use laxopeg sachet 
4. Also 
lactulose syrup 15 - 30ml during breakfast 
5. Rule out disorders like 
hypothyroidism, 
irritable bowel syndrome etc 
6. Bowel exercises. 
Hope I have answered your query. Let me know if I can assist you further. Get well soon. 
Regards, 
Dr. Yogapriya V, General and family physician.