Help?

Ever since i began getting the birth control shot (almost a year ago) i have had no period but spotting for the last 2 months of each 3 month shot period. Also sorry for the TMI but when i am having sex, its like i can go from being completely ready to not wet at all. And its not that im not turned on or that i dont want to do it, its all completely physical. My doctor said the spotting is normal but I’ve been too embarrassed to ask about the other thing. It makes me feel like there is something wrong with me.