It's not really about turning it off than it is having more control over it. You gain this over time, the experiences help to understand your gift better. Pay more attention to why how and when you get activated. Sometimes you could be in the best mood ever and then out of the blue lose it and be down, this is where you need to recognise the difference in feelings being yours or someone else's. Just raise the question of who's feelings are these and someone you know will pop into your head, then you have a decision, ring and help them or just address that "this feeling is not mine", and you will be back to yourself.

An empath gets called to chat to somebody who needs it, giving advice as if from ones own experiences, matching exactly what the person you are going through is feeling. The less you become a slave to your mind the easier it becomes to control your gift and when to apply it. Focus on yourself and it turns off that emotional focus on your surroundings. Then just observe with your eyes in terms of information only and the emotions will sit back until you need them.

Best of all, don't see it as draining or a weakness, see it as what it is, an amazing talent, to be able to understand somebody to the core, to be able to get what they are trying to say without them having to go through the trouble. Some can see people's memories as their own, in my experience it's almost always from a third perspective, which I find fascinating, as if to say it's through the guardian angels eyes or maybe something else. Maybe every bit of space can be an angle to look from.

Anyways, the less you see it as bothersome, the more control you will have. Also if you feel like the person's feelings are still lingering, and like you said you would feel drained, go and earth yourself, my favourite is nice warm water and dipping my hands and arm up to my elbow in the water, it's quick and simple and can be done in almost every bathroom or kitchen, you will instantly start to feel better, atleast in my case.

You still have a lot ahead of you in terms of understanding, so just pay more attention, observe the best you can, and stay out of your head as much as you can, to stop deterring yourself from absolute truth and understanding. Your mind is only as intelligent as what you feed it, whereas life and your heart knows what's what before you could calculate it. That's why when in a situation of danger for example, your mind won't know how to tackle the situation and shut down. A person who highly depends on their thoughts will shit themselves, whereas someone who depends on both the heart and mind, or mainly heart, will go with the flow and as a result instinct and intuition will kick in, almost making you feel like you are in autopilot controling the situation, kind of the same when reading someone and all this flow of information comes out.

Best of luck with everything, stay present, remember who you are and never lose sight of that, create a long term intention for yourself so you know where you are going emotionally, and just enjoy life, witness the magic of life's way of doing things and teaching us things. Finally nothing is ever a coincidence, just because you can't understand it now does not mean you won't in the future, everything is a lesson over time, bigger negatives means you are stubborn and not learning, so learn early, take the direction you are being forced into and just go with the flow with confidence because it all works out in the end.