I am self-teaching myself mathematics for a few years now and will suggest the following: Algebra and Trig, a subset of which is known as pre-calc. Don't short yourself on this because it is basic and you don't want to be struggling with it at the same you are struggling with the higher level stuff. I cannot recommend Sheldon Axler's Algebra and Trigonmetry highly enough. After much searching I found that and have been through it 3 times.

Next Calculus: I recommend Gilbert Strang's text book which will take you through what in uni is called Caculus 3, 1 being intro, 2 being differential and 3 being integral. I in the midst of this book and so can't speak to further but my plan is to move onto Strang's linear Algebra. After that, where to go depends on particular interest but leaving any of that out, in my opinion, will just handicap your further studies. Moder education does a lot of things wrong but the standard math sequence in use everywhere isn't one of them imo.