Monitor your heart, keep note of it. If it feels like your heart is straining or your blood pressure is a smidge too out of range or heart rate too high, take note of how much you've drank and the effects. Find your baseline "too much" and use that to find a sweet spot of "not too crazy heart" + caffienated sufficiently

I would say tea. It has a similar effect as energy drinks, but without the crashing and it's better for you. As for the alcohol, I'd say stop altogether. I've been sober now for a bit over 10 1/2 years now and I feel so much better without it. Also, try to stay away from red dye in things especially. Everything including caffeine needs to be in moderation. I know that it can be tough to do at times, but I can tell you that you'll feel better.