I was drinking three cups a day for a while but the hair loss and fatigue didn't make an appearance until a few weeks after I had upped the daily amount of Green Tea drinking to 4 to 5 cups a day. I've searched around but this might just be one of those little experiments that I have to try out myself to get a solid answer. I know dropping Green Tea completely could help but it has done too many miracles for my skin and fight against acne.. and it's got a lot of other healthy benefits as well.
The hairloss is something I've suffered from too and I know for a FACT it was from Accutane. Has to do with the sebaceous glands being so dried up during the course to the point where it affects the follicles of your hair on your head and possibly on other places of the body as well. It has diffused my hair a bit and I notice the difference like crazy but others around me who see me all the time don't seem to think it's that extreme. My money is that your hair did it's little hairloss jamboree because of the Accutane courses. Things should only get better with time for your hair, but if that doesn't really work, try using a thickening shampoo. I use one when I feel like my hair is looking on the thinner side and it works wonders!
Honestly I've been taking probiotics for a few months and I find them very useful in fighting off the damage I did to my body with antibiotics back in the day.. Haven't noticed any breakouts because of them because I refused to take the cheap probiotics my girlfriend said I should buy. Instead I purchase $40 probiotics that are for-sure Dairy-FREE as I have heard that this only aggravates the acne people have because it is dairy after all and dairy likes to make the skin explode (from what I've seen, heard, and witnessed on my own face). My suggestion would be to try a probiotic supplement that states that it is Dairy-Free and I'm pretty positive that you will notice a dramatic difference.