First I'll address the protein: If you're not getting enough protein in your normal diet, supplementing with some whey won't hurt you and could help. There's other supplements out there to help but it feels like you're not very familiar with supplementation in general, so you should take your time researching/asking questions (check the diet and supplementation forum, they'll probably act like assholes and tell you to check the faq but whatever, some people don't know what non private forums are for...).
Eventually you should stop getting incredibly sore from it (I'm assuming you're relatively newer to BJJ). You should also consider doing yoga, or at least stretching before/after class (dynamic stretching before class, static stretching afterwards, google the terms if you're unfamiliar). Stretching after waking up and before going to bed can also help.
On the days you aren't training BJJ you might want to go for runs, hit the rowing machine, do some body weight exercises in order to get blood going.
You can also use contrast showers (i.e. when you're taking a shower, end the shower with a couple minutes of ice cold water instead of taking a hot shower all the way through).
Make sure your diet is supportive, vegetables, fruits, etc. Hydrate yourself responsibly before, after, and during training.
Sleep as much as you can and stay active as much as you can as well, sedentary life interrupted with bouts of exercise is a good way to be sore all the time.
Hope some of this advice makes its way to you.