What I’m about to say may shock and confuse you–it’s okay, it’s not your fault; the machines are lying to you. But I’m here to help.
Your apostrophes are backwards.
Don’t worry, it’s not all the time. The most common writing software is just making things bonkers for you.
On fonts that utilize “curly” apostrophes (unlike online, like this typeface) should always have the “tail” of the apostrophe pointing toward the missing letters in a shortened word, such as in dialogue. In other words, the apostrophe should be “closed” or shaped like a number 9.
But Microsoft Word botches this every time, like this:
The apostrophes for ’em (them) and ’90s (1990s) should show the reader where the missing letters go. Thinkin’ (thinking) is correct, however; the tail says, “there should be a ‘g’ right here!” Instead, Microsoft Word thinks those apostrophes are single quotation marks, which leads it to put in the wrong one.
Here’s how it looks when it is correct:
Now our helpful apostrophes say, “look, these two words are missing letters!” Perfect. (And “thinkin'” is still correct.)
Individually, this is easy to correct: just put in two apostrophes when you want to flip one around. The second apostrophe will be turned the correct direction. Then, just delete the first one.
If you’re going to be apostroph-izing frequently, you may want to look into the programming to see if you can turn off the flippy apostrophes, but most people don’t need to go that far. Of course, you can also hire a good editor/proofreader (like me!) to do all the apostrophe-scrounging for you.
I recently worked on a fun book that featured a lot of Western-y dialogue. There were a lot of backward apostrophes to fix. Here’s an example of how this kind of dialogue should look when it is done correctly:
With all the shortened words spelled out, this would say, “That is because you run faster than I do, so as I gotta get them first.” But that just sounds crazy, so shortened dialogue it is! Just be sure to keep track of which direction your apostrophes are facing.
If you want to read up on apostrophe directions, consult section 6.114 of your Chicago Manual of Style, 16th Edition.
Are your apostrophes backwards? Have you run into this problem before?
M.E. Kinkade 
Very interesting! So here’s my question — if the curly bit on the apostrophe is supposed to point toward the part of the word that’s missing, why do our apostrophes in contractions point toward the full word? E.g., “that is” becomes “that’s”, where the curly bit points toward the “that”, not the “is”. Thoughts on this?
It’s fudged a bit, but the curly bit is still pointing to the missing letter. Imagine it as “thatis.” The apostrophe would go “thati’s.” A little brain-bending, I know, but that’s convention.
Ohhhhhh! I get it now. Okay, that makes total sense 🙂 Thanks!