Did you check the preload on the suspension? The rear shock has a bolt that turns, it clicks from softest to firmest, and every fifth click it'll go "bonggggg" and will be reset to the softest setting.
Note also that as you lower the bike, the geometry (leverage) acts on the shock in such a way that the lower it goes, the softer it gets. I have my bike lowered currently about 2", and note also that I have the suspension set to the firmest preload, and it feels about as soft as it did when the bike was at the stock height and the shock was set to the softest preload setting.
The two go hand in hand, so if you are raising the bike to stock height again, that will also act to stiffen it - if it's still not firm enough for you set the preload - if it's still not firm enough for you, then you'd need to buy an aftermarket shock/spring designed to be stiffer...
...or - raising links, if the bike isn't too tall for you at that point. That'll also increase your ground clearance, so a 2-for-1 for cheap, rather than 'just stiffer' for expensive. Tweak before you buy, IMO.
Last edited by geolemon; 08-13-2013 at 12:44 PM.