Need help trying to quit again

I deal with anxiety and periods of low mood in general, and smoking is definitely a bit of a crutch for me with this. I managed to quit for 6 months last year but I feel my mental health really took a hit so I started up again. I read a lot of posts here where people talk about the positive effects on their mental health when they quit and I really can’t relate, unfortunately. I am currently on 100mg sertraline daily for anxiety but have been up at 200mg in the past. Has anyone in the UK had experience asking their GP to up their dose to help them quit smoking as I think that’s what I am going to do. Thanks.