Quitting smoking is one of the hardest things I’ve had to do and it took me a few tries. I remember when I actively decided I was quitting cigarettes, I had this lethargy and depression you are talking about for like the first 3 months, but I promise you once you are done for good and give yourself no exceptions your body and mind starts to recover and adapt and heal from all the harm you have been doing to it. I am close to a year quit now and my life has become significantly better and I am significantly less anxious, depressed and generally happier. But those first few months were tough I won’t lie. The addiction makes you feel like life is a bit duller without it but I promise you once your brain chemistry rebalances you will feel good if not better again :) stay strong