Husky McHusk

Hey guys,
I'm a 23 yr old male 6'1 195 pounds.
3 years ago I weighed 220+ pounds and decided to change all that by hitting the gym and hitting it hard. I did cardio, weightlifting, and my diet was very clean. As you can see I lost around 30 pounds.

While trying to lose weight I was pyrammiding sets 16-14-12-10 at heavy, but reasonable weights. Realizing I got down to a good weight I started trying to build more muscle.

Now my sets look like 10-8-6-4...I'm benching almost 300 pounds which is more than I ever could, and I'm doing huge amounts of weights compared to my friends and gym partners. For taking only protein and creatine, I will say I have made tremendous gains.

I am looking pretty good these days and I have built alot of muscle and receive compliments almost daily for my hard work. But My question is: Why am I more hungry now than ever? I eat healthy food but I eat constantly. I have to be around 4000 calories a day. I'm not putting on any fat because my waist size is still the same and my weight has only gone up a 2-3 pounds in 6 months. It seems obvious that my body is needing excess calories to repair the muscle fibers I am destroying in the gym. Is this healthy? Do you think this many calories a day is beneficial? Does it have to do with my age and the high amounts of weight I am lifting? Should I continue with this regimen? For some reason I keep thinking its gonna catch up with me and I'm gonna be fat out of nowhere.

Thanks for any info you can add.