@Panda Eyes
Mate there is absolutely no need to go balls to the wall at your age and fitness level.
No rest breaks is a very specific advanced process that you only use after lifting weights for several years.
It was irresponsible for the trainer to push you that hard and I would stay away from them from here out.
If you want to do cardio then go for a walk for half an hour to 45 minutes per day. That is ample for everyone except perhaps for bodybuilders getting ready for a competition, and cardio specific sports such as cycling.
If you want to build muscle/strength then you need a program to specifically do that.
Muscle is what will make everything easy, cardio is a very distant second. You said you've got decent size and as you lift more the fat will come off you and you'll change shape. You won't gain actual size or weight for a long time.
On the food front, you should eat roughly 1 hour before lifting weights and it should comprise of mostly carbs, 50 to 100g depending on amount of muscle carried.
Mate I've done all kinds of lifting over the past 7 years, have worked out what works for lifting and also for diet. I'll be happy to help you get into it, without getting injured or put off by negative experiences like you've had.
Yes you gotta work, but no where near as hard as people think. You lift smarter, not harder. On that note, to be smarter you need to learn a lot. That I can help you with.
If you're keen send me a pm and we can work out (no pun intended) where you're at and how to move forward.
Last but not least, it's easy once you get into it and 45 minutes, 3 times a week of weights will absolutely change your life.