Is this black hat? I think I got google-slapped...

I noticed yesterday that one of my inner pages which I had ranking pretty high in Google for several keywords for several months now had disappeared from the SERPs....completely! It is still in the index but as far as the SERPs....nada. And it must have been gone for a couple of weeks already because thats when I first noticed a considerable dip in my traffic...but since it was shortly after Xmas I didn't think much of it. Now it's a different story...

After much deliberation I think I was able to pin down the reasons for this disappearance and I would like to know from you guys if I'm right about this. I already made the changes so here's to hoping that this will get me back in Google's SERPs.

1) Shortly before Xmas I had made a new page that contained some of the products I had on the page that disappeared. As a matter of fact, I had the pix and description just pasted in from there. So I guess this new page had about 1/3 of the page that disappeared. Is this enough to trigger the duplicate content filter and get me out of the SERPs?

2) On the new page I had made all the product titles into backlinks to the original inner page (the one that disappeared). Since these are all similar model names and they're all listed in succession, albeit interrupted by the descriptions, could this be considered black hat?

3) All these "title links" I had in plain font. Usually I make all my links in a different color but since in this case they were also product titles I used the normal font. Again, is this considered black hat?

Now its possible that it's a combination of all these 3 that got me slapped. But I would like to narrow it down so I know better for the future. Thanks!