Has my site been hit by Penguin/Panda?

I've been working on an authority website since Last December & all of a sudden, my keywords are no where to be found in the serps, just 2 days ago most of them were on the first page. I didn't change anything or do any notorious backlinking, so I logged in to webmaster tools & on links I see 1 link that seems to come from a scrapebox blast & possibly there is more to come. I didn't do any scrapebox blast(I don't even have scrapebox) so I'm suspecting some dick blasted my site.

This is bullcrap btw, doesn't google know that website owners don't have complete control over this? Anyway they just invited lots of spam I hope people start using other search engines.

Does this seem like the site's been hit by penguin or panda? Is there any way I can get the keywords back into place?

Its quite possible. Without seeing the site or analyzing the backlinks, its hard to tell. I can tell you for sure if you PM me the URL. I'll run a report with MajesticSEO and take a look at the link profile.

what is the date that your serps tanked?...this will help us know if panda/penguin affected your site...

Between Monday & Today

Then no. Your website tanked due to a general algorithm change/devaluing. Penguin/Panda are refreshes that occur at specific times. We'd have known by now if there was an update/refresh; and there wasn't.

It's also possible your site will just pop back up in Google in due time. It's pretty common for sites to pop into the Google Sandbox at some point in its lifetime, even if the site isn't new and you didn't do anything wrong. If you're really sure you didn't do anything wrong, just check your backlinks, make sure everything's OK then submit a reconsideration request.

As you said, you could find only one link which seems to be from scrapebox blast. And you are assuming that many more will come now. Have you checked that backlink manually and does it really look like spam. It might be genuine blog comments and that can not be classified as bad link. G is updating their algo every now and then and it just disappears sometime. So give some time and it might bounce back to its original position.

My webmaster tools reported loads of new links this morning.
when you go to traffic -> links, there is a list of links

This list is not updated everyday but every once in a while, and my list was updated this morning, so there was some sort of an update today.