Welcome to SR and posting. I have only experience with quitting alcohol but I can say that the hardest times I had came at around the 6 month mark. I was feeling physically better but mentally I was all over the place. Very angry a lot of the time. Had a horrible time getting up and going in the morning. I just kept going.
What are you doing for your recovery besides not using? Do you have face to face support? I needed that support and to be around people who were actively working on their sobriety. I desperately needed a well managed routine to keep me accountable and to retrain my brain into knowing that alcohol wasn't the answer to any of my problems.
Read around, keep posting and keep coming back.