I knew about crypto at the end of 2017, after a short time increase and make people crazy to invest, everything is down now. I'm not a trader, i'm just a holder, but i'm still afraid of the sign of market recently. Will everything be changed in next year? or several years later? Can i still invest in crypto?
Yes it will changed this year,and to the next upcoming years 
do not be worried about these market crashes,holders will always win the game for the longer terms all you need to to is relax and do not check the market regularly because a holder should have less stress than a day trader,enjoy your life do not do what others are doing because its stressful.