My knee keeps cracking, help!?

So i had knee surgery in November for a meniscus tear, and i know this sounds so extremely stupid so i dont need side comments, but i went back to sports right away because the pain didnt reall bother me that much. And by sports i mean trampoline where i hurt it, but the swelling never went down and now it starting to do this painful crack. Like extremely painful, and my knee would crack probably 2-3 times a day. And i never thought anything of it because my knee never locked like it used to, so can anyone tell me what's happening? And id rather not go to a doctor because my parents cant pay for a second surgery and i have volleyball in august. Thanks!