Have Forum profiles killed my site?!

I add good quality, unique content to my site a couple of times a week and have done for a few years now, the site is just over 200 pages deep of decent quality content and had 3 1-5 position rankings for my main keyword.

Backlinks wise I have mostly just been building forum profiles day in day out 10-20 per day, mostly to try and grab some long tail traffic by directing them at my inner pages but admittedly some pointing to the homepage also. Over the past week traffic has dropped and looking at serp checkers it looks like all my highly ranked pages are waaay down the serps at 200-300 positions.

Now, two of my top ranking pages simply appeared in the serps one day without me having built any links to them, and looking at other high ranking sites many of them have minimal links, I however stupidly I didn't see this relationship and thought oh I better point some links at them to try and 'keep them there' (links being forum profiles) So I now have to assume these links are the cause of my pages losing their ranking.

One other thing is that a couple of months ago I did purchase some fivver backlink gigs and some backlink services on here which I assume used forum profiles too so could this maybe be the reason for my loss of rankings or at least a contributory factor?

What I'd like to know is what do I do now, my site was just beginning to bring some traffic in now it's all but gone. Do I just stop the forum links altogether and continue adding content and spend my time searching for high quality links instead (which I have done in the past with very little success which is why I had began using forum profiles!) or do I continue what I have been doing over the last 6-12 months and hope this is just a bit of a dance and that my rankings will reappear soon!