I’d also like to congratulate you on your promotion, and agree with the general consensus - although, if it is imposter syndrome, it’s relatively easy to work through as long as you approach it consciously and are consistent until you feel better about things. It takes time and effort, but it’s doable! It’s natural to worry about having more responsibility, in any case, but clearly your employer can see what you have to offer, so this might be a decent starting point to challenge the belief that you’re not good enough.