iMac running super slow, especially after restart

Looking over your EtreCheck report the only thing I see is that you seem to have the wrong computer for they type of work you use it for. It appears to be a base model 21.5" with only 8GB of un-upgradeable RAM and a glacially slow 5400 RPM HD. Those machines were only intended for doing e-mail and surfing the internet however it appears. you are running professional grade apps on it. However if it was running better a couple of weeks ago, then you may have a hard disk issue which would not be surprising on a 7 year old computer. I would recommend restarting in the Recovery Partition (Command + R on startup), open Disk Utility and run First Aid 2-3 times and look for errors. If any errors appear that confirms the HD is in trouble. That being said you would need to take it to an Apple Authorized Service Provider to be professionally diagnosed and repaired.

Finally and MOST IMPORTANT you do not seem to back this computer up. That is a 100% guarantee of losing data!!!!!!!!!!!!!!! At the very least you should be using Time Machine to backup hourly. Operating any computer without a sound backup plan is foolish and short sighted.