19 is a little young. There are probably a lot of things you still need to learn about training and diet to get the most out of gear. Even if you get it nailed, it takes time. You need time to grow and then hit plateaus and then figure out ways around them. If you're too skinny, it's either your diet, your training or that you haven't had enough time on a good diet. The thing is, you don't need gear to be the size of a fitness model. I'm not telling you that you shouldnt use. Thats your choice, but you can do a lot with your generics still. You just have to learn how to unlock them. 

As for gear and sex...yes, this is common, PCT or not. But PCT would have nothing to do with almost dying! That had to be something else. Steroids shut down your natural test production. This is what regulates your libido and allows you to perform in bed. Even with the best PCT, you can have problems in this department. If you abuse gear, taking too much or staying on too long, you could have issues for the rest of your life and require HRT. You don't want that at your age. So if you are going to use gear, keep this in mind and be aware that even with the safest cycles, you are taking risks. 

There are many more potential problems that would lead me to suggest waiting on gear. If you are dead set on using, please come back and talk to me. I will help you because I would prefer you were safe and being watched vs listening to some jack ass in your gym that doesnt have a clue what he's saying. Remember that gear or no gear, this is a life long sport and you want to think about the long game. So take your time and keep reading. Stick around the Q/A, ask questions and more importantly, read the answers I give to others. There are a ton of new guys asking questions you probably have. 

A good age to start would be 21. At that point, you will also have learned a ton and built a solid base to grow from. Then adding gear will take you that much further. 

So once again, if you are dead set on it NOW, take at least a few more months to read more here. Send me another question, reminding me of who you are and I'll help set you up. I know that for a lot of younger guys, its hard to afford a coach, but if you have the means to hire me through the Next Level Nutrtion page, here at Naps, I would be happy to give you one on one adivce and walk you through your gear plan, diet plan and training, week by week. 

Take your time and think about this. It's a big decision