Did you buy freebase or salts? And what mg/mL did you dose at? I still use my reusable vape and dose my own and have dosed both freebase and salts - what MalReynolds says is the truth. The salt has a much lower throat-hit, which has allowed the disposable vape companies to jack up the mg/mL to 50+ which is just fucking insane territory. A friend of mine dosed his own with nicotine salts at 50mg/mL to compare and it gave that exact head spin you’re talking about. It’s a combination of the dosage and use of nicotine salt that does it.