why do i feel so unprepared ? in biology

title, i have done everything once (weak parts 2-3 times) and revised everything atleast once too, questions bhi ho jaa rahe hai but andar se satisfaction nahi feel ho rahi, like deep revision nahi hua hai yeh lag raha, kya karu mai? aaj poora din bio ko dedu? kahi exam wale din overthinking na karne lagu, please help (fresher who had normal school and offline coaching, idk because of this i feel like i got way less time to prepare and thats why i feel unprepared) help seniors please