MacBook lagging on every task

Over the past week my MBP has suddenly started lagging on every task, ie opening a new finder window or typing a web address- spinning beach balls. Don't really know what changed. Didn't make any big changes that I'm aware of.

Yes, I did upgrade to El Capitan but AFTER this began in the hopes that it would somehow resolve it.

About 4 months ago I put in a 500GB SSD and 16gb of ram after which the MBP was running great. Problems appeared about 7 days ago.

I ran cleanmymac3 and deleted some things and also bitdefender which found 9 "infected" files which it claimed to have resolved,

What do I do next!?

Dropped it off for diagnostics at a local indie mac repair shop. They diagnosed the SSD drive as failing. Apparently they tested other drives in my computer with no problems and replicated the same issues using my drive in other computers. Bummer. Under warranty but I'm surprised at the failure. Hopefully a fluke and I guess OWC will have to rush me a new one