Cardio dropped after quitting smoking

I’m 27 been smoking weed & tobacco (mixed together) since I was 17. Been training for 3 years and competing for 2. I decided to quit after I won my last match but had a bad 3rd round and my coaches called me out on it and said I needed to quit. NOW THIS IS THE IMPORTANT PART! It’s been about 9 days and I can’t go 2 rounds of sparring without running off the mat to vomit (water I don’t eat before class) it’s not my lungs because they aren’t burning or anything. (Like after a fight) So far I’m just assuming it’s withdrawals but I don’t like making excuses for myself. I’m just wondering if anyone else has experienced this.