Signs of a DOS attack?
 

Recently I had my network go down (not just my internet), after a few minuets, my network went back up, but not after I logged a large amount of activity coming from the IP 78.60.137.44. Upon checking my firewall, it said a specific IP address was sending fragmented TCP packets (among other things).

According to a quick google search, fragmented packets are commonly used to expose weaknesses of a network and propagate an attack. Question is, was this a DOS attack and if so, what should I do to prevent a subsequent attack or make sure my network/system wasn't compromised?

Maybe it was just a port scan.

Probably random internet background noise, from someone who has a crawling botnet.