Word's..?

I'm having a terrible time recently with my use of apostrophes. I keep saying that I used up all my writing ability to get my novel done. Like I sold whatever talent I may have had just to get the thing done, and now I'm relearning, and it's so damn difficult because sometimes I can't figure out if I'm even using an apostrophe right. But I try. And I think. And I keep on moving forward, because that's the only thing I can do... hugh...