Any Help Would be Greatly Appreciated

I am new to this forum and new to Facebook advertising. First of, I just want to thank everbody in advance for replies in this thread any help would be appreciated. On November 2nd, I started paying for advertisement on Facebook. I did a couple test campaigns before November 2nd and got some positive responses. Basically, the best response for my ad was about $.29 CPC. So on November 2, I ran a $100 ad for one day between the hours of 9am and 6 pm. I got some calls and a lot of web forms filled out on my landing page which was great! So, I did the same thing from the 3rd to the 6th and overall it worked out well. Basically, the my cost per lead was right around $6, which I was happy with. Now this week is a completely different story. I didn't run the ad today because Monday and Tuesday its cost me around $35 a lead. To make a long story short, I have a couple questions;

1. Does the cost per lead fluctuate that much from a week to week basis?

2. The more and more I ran the ad, the CPC kept increasing, my target audience was right around 250k. Is this normal?

I also forgot to mention that the landing page and ad was never changed. Sorry for the amateur questions, any input would greatly be appreciated.