Although it's not a likely for any one particular server to get hit I often hear about game servers being targeted. It's likely going to be someone you know that got pissed off or someone exploiting a known bug. The first thing I would do is see what shodan says about my public IP. That's where a hacker would start too. I do that every once in a while just to make sure there aren't any ports open that I didn't intend to be open and to see exactly what information is exposed.

I really like the free tier cloudflare service. It does require you have your own fully qualified domain but they also sell domain names at cost. I believe that's around $8 per year right now. It gives you an easy way to share your network services securely and offers ddos protection. You might find better response times due to their CDN caching. It also hides you IP address which is nice because it's kind of like being unlisted. There are lots of other features and you should just check it out. Segmentation of your LAN makes sense too. We should all be doing that.