Why am I having such a sudden extreme hairfall? Recently I've been taking tensions and my hair are just falling out in one brush? Any useful remedies for this long hair losing?

I can make a long list of the causes of hair loss & things we need to take care of to make sure things about our hair would be on routine.

But you made it short,

"Stress" is one of the factors that cause "hair loss" try to calm yourself & relief your stress. As soon as your stress & tensions stops, your hairs won't fall anymore.

Based on your other question it might be stressed related. Why not go to a doctor for an exam and see if you may have some sort of chemical imbalance.

I noticed my hair thinning in late April of 2015. I have been taking HairXT100 since then and have been very pleased with the results. I do eat well and exercise regularly and have for most of my life as fitness is my profession and hair loss wasn't very prominent in my family so this was a surprise. Most people claim to see regrowth with this product in 4-8 weeks, but it took me about 10 weeks. Hope this helps & good luck!