Bitcoin Client Software and Version Number: Bitcoin Core 0.15.1
Operating System: Ubuntu 16.04
System Hardware Specs: 2.4 GHz Intel Core CPU with 16 GB RAM and 750 GB free hard drive space.
Description of Problem: bitcoind refuses to start up. Keep getting the same error over and over.
Screenshot of the problem: https://imgur.com/pj2KFrh
debug.log: https://pastebin.com/2LCw5BJt
bitconi.conf: https://pastebin.com/ZsQArYRy

I am a noob trying to get into blockchain development. I have been running my own node for a few weeks with no problem. I shut down bitcoind at the end of each day, I only use it to practice.  I have a SSD boot and a HDD storage drive with 750GB.

Yesterday I started to have problems with starting bitcoind and had to -reindex. I stopped bitcoind and got home today to restart it once again and yet again had to -reindex. I have NO idea why and quite frankly there have been absolutly no helpful tips on the internet regarding this. i hope someone here can help me. I have the entire blockchain on my HDD but I cannot even start bitcoind anymore. Any help would be greatly appreciated. Thank you.