My Dr Had Me Stop 300 Mg Effexor After Several

My Dr had me stop 300 Mg effexor after several yrs use and 40 Mg (per day) hydrocodone after 5 years use. He subbed 20 Mg lexapro and 8 Mg (per day) dilauded. I was concerned about withdrawals but had faith in what he was doing, Long story short. 10 days of sheer hell. Should the new Meds have prevented withdrawals or should I have a very pointed discussion with him?