I work in a the Marketing Department in a role that essentially bridges the gap between IT and Marketing, if there is anything technical, it basically falls to me to be the one to implement it, this includes reporting, marketing automation, other day to day tasks and bigger projects. When I first started in the role, I was given a fair amount of autonomy, which I was able to turn into strong self development and also a promotion.
The problem I am having is in relation to the bigger projects, and the fact that I get about 90% complete with a project, and the spec "slightly" changes, in the eyes of the manager(who is not technically minded, as he works in marketing), but it actually means that it's at least an extra afternoon's work, if not a couple of days, bringing my overall completion of the project back down to 40-70%, which I find very demoralising, and I find it hard to remain motivated on the project as this can sometimes be a never ending cycle(turning a 3 day project into a 3 week ordeal is not uncommon), I also personally feel like I am not performing. I have spoken to my manager about this, and he seems to think I am performing excellently, but personally, I am finding it very unfulfilling.
In addition to this "rework" cycle, he also gives me "pointless" projects with no business value, which can take a day or more to complete, either due to the fact they are rather complex when it comes down to implementation, or the fact that the spec changes after completion that I am forced to redo the work. I would not mind this, if I actually received credit for the work, but on the emails, the word "I" is used in place of "my name" or even "we", leading me to worry how I am perceived throughout the business, not just by my manager
Overall, I feel like I am being poorly managed, but I know I am probably going to have to "manage the manager".
My question is really two parts, is any of the above normal, and if so, how can I deal with it