Metrics are important. They give you a way to track how well your marketing efforts are doing. But your number of likes, followers, and comments shouldn't rule you or ruin your day. Don't obsess about them. I know; it's easier said than done. We all want to be liked and recognized. Rejection hurts. It doesn't feel good when you get "unliked" or a crummy review.
Look at your numbers. See if you can find clues to figure out what happened. If your site visits on your blog drop, and you haven't been posting, then that's a good sign you need to blog on a regular schedule.
But remember that people are fickle. There is a lot out there to capture their attention, and they often unlike things willy nilly. Don't fixate on the negative. When you lose followers or get negative comments, see if there is anything you can learn from it. If not, let it go. You can't control other people. Go exercise, shout, or jump up and down. Get it out of your system, and then get yourself back in your chair and write. Your primary job is to finish your next work.
Social media has two parts, and the first word is key. People like when you have conversations and build relationships. I always thank people for great comments, reviews, or shout outs. But I don't comment on snarky or negative comments. You don't want to get into a war of words that will last for ever on the Internet. It's hard not to respond or defend, but don't post anything you'll regret later.
Best wishes for your writing! It's hard work, but keep at it. You're not going to please everyone. Celebrate the successes and learn from the less than sterling ones.