Is It Supposed to Act Like This?

I admit that I really didn't know all that much about modern computing when I got my Mac a year ago.  I had barely used any computer for anything in over twenty-five years!  At most, I was using public library computers for internet searches and the occasional download/print job.  I only had a 'personal' email account for about a year, maybe two.   I was on Facebook, had my blogs, and even fixed up a website for my store, Booknotes, and all without a computer.  I was barely online four hours a week, total.  Now, I can't see how I was able to manage all I did with so little time.  That is the main reason why all my early blog posts were so short.  Even now, I try to maintain the same length of time.  My biggest problem now is trying to be sure I am not making huge mistakes.  In just the past few days, my Mac started to act up a little.  Nothing major, and maybe not its fault, but it is concerning.  Just yesterday I had to start up my Mac twice because the first time didn't really take.  I get afraid that I accidentally downloaded something I shouldn't have or I set something up wrong.  I don't think I have done anything too bad, but the dread is still our there.  Maybe I did the last upgrade for Mojave wrong.  Maybe I downloaded something that only pretended to be an upgrade.  Maybe I am just playing too many games for to long a time.  Hey, I have very little to now with school out, a failing store, and no real social life.  If the wifi at the store wasn't so iffy, I might have been playing even more than I do now.  I have digital copies of multiple books, as well as some of my better school projects.  I deleted most of them for room.  Sure, I should upload some of this to the cloud, if I could ever figure it out.  Then again, I like being able to do things such as this at a moments notice.  Although that line up above is disconcerting, even if it did just fade away.  Text wrapping is also an issue, but that is more with Blogger than with me.  I'm only including this pic so it will show up as a 'faux' icon on social media.  It still won't work with the Blogger interface, but I think I can find a work around.  Now, can anybody tell me what is going on with this thing?