p90x doesn’t work

I just can’t gain weight! Help please?
Hey I am a 17 (almost 18) year old male who weighs about 95lb and I can barely gain weight. For the past two months I have been working out using P90X and irongym and taking protein shakes and weight gain shakes and eating a lot more, including healthy foods too. I still am about 95-96 pounds on my scale, I don’t know what is wrong. People tell me to weight lift (which I have been doing) to build muscle mass but doesn’t that just burn calories? Isn’t it better to just eat a lot and get fat then work out and convert it to muscle? What should I do? I am just puzzled I really need some pounds, thanks!
At your age your metabolism is probably supper fast. P90X is designed to tone your body and help you lose weight, your probably doing too much cardio. You need to lift weights, low reps, heavy weight, no cardio! Research powerlifting routines which focus on your biggest muscles, and stick to one for 3 months. Sites like bodybuilding.com have lots of routines you can look up and lots of info to educate yourself. As far as eating goes, you need to eat a lot, to gain weight you must take in more calories than you burn. Start a food log and track your calories. Keep eating healthy, no it’s not good to get fat and the try and work out, muscle weighs more than fat so focus on building muscle. Your young so keep at it and you’ll see results, you may not have even hit your growth spurt yet..you will.
BeforeP90X