Just like the price of bitcoin can go down to over 10%+ in a few days, It can also go up by the same amount in both cases there is this Snowball effect and some exchanges utilize a stop-limit so some traders might buy in at 10000+ since they know it would continue rising, the price of bitcoin at the time of writing this post is at around 10200 so regarding the OP I think 10000 seems like a reasonable support, especially if it ends up hitting 11k tomorrow this would slightly ensure it wouldn't go below 10k I mean it most certainly could.. in the end of the day bitcoin is unpredictable so HODLing sounds good