Wow. That's alot to just stop taking... The withdrawals will be severe - it's possible to do it but it will be pretty bad. Honestly? I hate to say this, but I wouldn't recommend going cold turkey like that. You're taking 2 very strong opiates... If you really want to stop them - is tapering an option? You could definitely ask your doctor to help you plan it... The ativan alone you really should not be just stopping, that's supposed to be tapered due to side effects.
Assuming that these were prescribed for you, a responsible doctor would just "not refill."
If you don't need the meds anymore, work out a plan with your physician for withdrawal.
Please let me know.