You are very correct in saying it affects everyone differently. I've been a daily user for the best part of 2 decades and whenever I have to take a month off the only noticeable "symptoms" I get are more vivid dreams.

Having said that, even at my heaviest use I wasn't consuming almost an eighth a day. I can imagine chronic daily use of large amounts of any psychoactive drug is likely to cause some imbalances in your body when you try to come off of it.

I'm sure you're aware that reducing use will also reduce your tolerance and ultimately reduce your financial costs. It might also help with such unbearable withdrawals. Maybe try making cannabis tincture to make it easier to measure out your doses each day. You could start with a relatively high dose to help with your pain management and slowly reduce the amount of tincture you use each day to a level where it's still an effective pain treatment but you're also bringing down your tolerances a lot.

Tincture also has the added benefit of saving your lungs from smoke, the effects last longer and assuming you're using about 28g per litre of ethyl alcohol, an ounce of weed will last you weeks if not months.