Nothing will beat practicing actual questions but to really lock down some concepts videos sometimes help.
My recommendation is go through the Lord 3blue1brown's lockdown fundamentals series, then his essence of calculus. Other YouTubers like blackpenredpen, Dr. Trefor Bazzet, minute physics, etc are also great.
Practice reading through a textbook's explanation of a concept to understand something, it personally took me a while to get my reading comprehension high enough to understand some of the "math jargon" used in many textbook's but learning to teach yourself is a big step in mathematical maturity.
Good luck OP!