Beginning of this year I see BTC and altcoins markets are higher valued. But Since Feb of this year thats markets are falling down. Its still not yet stable and i see lot of Panic seller in this period. I want to know whats the reason for it. Please give any idea 
No, it is definitely pretty stable around $6,500 for the last few months. As well, the market was just at like $10,000. All of these things are normal cycles of Bitcoin market, I'd suggest you check previous years month by month to see it is normal behavior, although different prices it is at. Just like at the end of the year it is typically pumped or gains value...it loses early.