My stomach i finally flat from being paleo, but I had to cut so many things from my diet to remain paleo that I'm now at 2600 calories a day. I get enough protein and fat, but don't know if this will just get me cut instead of bigger. I workout intensely so please give me tips. Thanks

how many calories were you eating a day?

What does your training plan and diet look like?
How long have you been training?
What other activities are you doing outside of training?

My diet is a dozen eggs a day, 4 hamburgers 75% lean, an avocado, and 4 servings of olive oil.

That's it?

I work out 5 days a week, 2 days for recovery.

I'm going to guess that you are training with a body part split?

I lift heavy and do calisthenics at the end of each workout. I do loads of negative reps as well. I am getting built I just want to know if this would be able to sustain another 20 pounds of muscle. I am 5"65 weigh 142 and I am aiming for 160. I have been training 2 months now. I am moderately active out side of training.

20 pounds is a LOT of muscle! That will take years!

Calisthenics aren't going to help you add muscle. Negatives are just going to cook your central nervous system and not do much for your training.
Good reads-
http://muscleandbrawn.com/forums/real-results-workouts/6460-rate-drug-free-muscle-gain.html
http://muscleandbrawn.com/forums/real-results-workouts/6458-your-maximum-muscular-bodyweight-measurements.html
http://muscleandbrawn.com/forums/real-results-workouts/6463-maximum-drug-free-bodybuilding-potential-ed-1-0-a.html
Necessary investment -
http://www.aasgaardco.com/store/store.php?crn=199&rn=312&action=show_detail

Well I am limited to what I can eat (can't have too much iodine because of thyroid which means no fish, and I can't do added sugars). I was also eating a pound of chicken breast in addition but learned about gluconeogenesis which makes the excess protein turn into carbs which I am not looking for. And like I said, I only eat 2500-2600 calories, and that is that exactly. Negative reps I find build me more than anything. I do 2 regular sets, then the last one I do negative reps of a higher weight. I vary my workouts over a 20 day period, no workout is the same and each set contains a different number of reps to prevent plateauing.  I don't know what foods I can add that won't make me fat but will allow me to gain pure muscle.

It may seem like you're not gaining fast enough though or really not at all at times, the key there is having realistic expectations.

Realistically, adding 20lbs of lean mass is likely going to take years of work.  Lean muscle comes slowwwwly, and there are time when you might not even see much of a scale difference for months if your body is recompositioning itself.

That has been my experience so far at least, my weight isn't increasing fast but I'm gradually becoming more muscular and vascular.