Why am i bad at tennis?

both my parents were all american and i think i inherited their talent. I know i have some talent in it but i started off rough, i've taken a lot of lessons since though. Since the lessons i thought i would've improved because i'm trying to get rid of not moving quick enough, late preparation/timing, using my arm and wrist/bad technique. In the lessons usually i do quite well but when i play i do much worse than i'd want. I'm not looking to be amazing or anything but there's so much to focus on that i overthink instead of just "letting it happen" i guess. I don't practice very often now so maybe it's that i don't practice enough for it to be automatic. I've tried playing with my coach but it's not the same and it's not like i can bring him and have him watch what i'm doing wrong in a regular match with other teens. what do i do?!