you sound like your eating the right food bro just not eating enough thats all. i know theres science behind how many calories you need and theres large value in that. but i also live by another rule of thumb, dont try and outsmart your body, listen to it. just because on paper your eating enough yet not gaining weight doesnt mean your still eating enough, eat till your consistently gaining weight. as one said, bump up your macros during a cycle and continue to eat a surplus after. you know how tons of idiots say once your off steroids you lose all your gains? the single biggest reason people say this is because people dont know how to fuel their body properly and eat enough. if your taking a ph to aid in body weight your not doing it right. but yes 13 pounds is a good gains to shoot for.
im not trying to be negative though, you CAN turn this into a positive. if you start bumping up the food intake now and continue to do so, you can continue to put on weight after your cycle which will severely minimize your strength loss post cycle and allow you to really enjoy all this hard work your putting in.