Macbook getting high CPU usage and not responding when on Skype/playing music

So, I just turned on my Macbook yesterday, and whenever any sounds were played (like Skype or music, etc.) the whole computer would start to lag, the program that was causing the sound would stop responding, and the fans would go up to max speed pretty much instantly. From a glance at iStat, i could see that my CPU usage was at around 90%, and memory usage was around 70%. I opened up Activity Monitor to see what was up, and kernel_task was hogging everything for some reason. I turn off skype and wait for about 5 minutes and it settles back to normal. I run skype again today and i end up being able to use any other program apart from skype, which freezes whenever I open its window and keeps on lagging and being silent when I'm in a call with someone. In the end, I just muted my computer and went off Skype, because the call lag was becoming unbearable.

Is this an issue with Skype, or is my Macbook just going crazy? It might also be worth noting that I use an audio program called LineIn to pass the sound from my PC to my MB, which has headphones in and is usually used to run skype while working on the PC. I've been using it for some time now and have had no problems with it yet.

Thanks in advance,

Joe