I'm a blogger, running the same site for seven years. Last month my traffic dropped by about half and I panicked. Let me walk you through the process step by step, hoping it helps others in the same situation.
First step: verify if it actually dropped. Check the measurement itself before panicking. I had three possibilities — the tracking code might be broken, the site might be inaccessible, or traffic really did drop. It was the third one, but ruling out the first two took ten minutes.
Second step: which pages dropped? If the whole site didn't drop equally, that's valuable info. For me, almost all the dropped pages were in one category.
Third step: is it a technical issue? A section accidentally blocked for robots, broken redirects, server errors. I didn't have any, but checking was a must.
Fourth step: don't rush decisions. I was tempted to delete a hundred pages, rewrite everything, change it all in the first week — I didn't do any of it. Good thing too, because partial recovery started in the fourth week.
I'm currently at about three-quarters of my old level. Haven't fully recovered, but at least I didn't make things worse by making panic changes.