So does this mean that on December 7th Ethereum is going to move to POS? May be this big dump before upcoming huge pump after hardfork

Hope to see good altseson again

No, this HF has nothing to do with the POS. There is no certain date for ETH 2.0, just rumors that it will start in Jan 2020. It is not clear whether a full POS will be introduced, or mixed POS/POW at first for better security. Full POS may happen still in Q1 2020 if there are no bugs.