I’m drained! Is this normal?

I have been breastfeeding my 2 year old for 2 years now. I was so excited and proud of myself that I was able to produce so much milk. I have been trying to stop for a while now but it has been too hard. My son is way too attached to me. While I am breastfeeding him now I just broke down crying. Every night I lay with my son to try to put him to sleep and it takes about 1 hour to up to 2 hours at times for him to fall asleep on my breast. I have been trying to stop for a while now that it got to me right now because I am drained. My son falls asleep on my boob and breastfeeds all night long. I literally sleep on one side because he is on my boob most of the night. I wake up with stiff necks and sometimes sleepless tired mornings. I love breastfeeding my son, but I feel like I have had enough. Mommas is this normal and how do I go about stopping? I have tried normal milk but he refuses once he is laid in bed. I still cosleep with him and if I do not he will cry nonstop until I finally give in. Help and advice welcomed! Thank you in advance.