Why did this coin fall so much over the last few days? I am very sad. What are the news on this project for the next month, which can positively affect the price of the coin?
You should better ask "why did it rise so much in the last months?".
The reason is obvious ... the IGNIS airdrop on December 28. After that event, the price naturally is falling again to its previous level. It was at <100 million market cap in November still. Now it's on 500 million, without any other airdrop in sight. Not bad.
If you had NXT on December 28, you should have IGNIS now, and be happy - they're trading at 1-2 USD. If not (because you bought later), then the best you can do is to actively promote NXT usage. It's a solid coin, the first really working Proof of Stake platform, and there are lots of use cases.