Possible intrusion ,please advise

I was looking at my wifi list as I do time to time and I noticed that my IP which should be 192.168.1.# wasn't there, in it's place was 169.254.19.##. Now I looked up that IP and it's some sort Quote:

Computers use addresses starting with "169.254." when they do not have a manually configured address or when they are not told which address to use by a service on the network. They are commonly called the "link local" addresses

so could it be someone has hacked into my computer or not. This is a mac, i know that's looked down upon here but I also use Linux on my other box and an odroid. So should I panic? Also before this happened I was messing around with my local address to fix a wifi issue, changing 192.168.1.1 to .192.168.3.1 and vice versa. Also I keep getting this pop up box saying, Another device is using your computers IP address (192.168.1.1)