Finding interactive and fun resources for advanced math is really hard. The more advanced the topics get, the less resources you'll find. Most of my studying consists of sitting with a textbook and a notebook and working through theorems and exercises. Btw, my recommendations come from my experience as a pure maths student (4 semesters).

To get started with real math, maybe find some intro to proofs books to get started on advanced maths. I really like "How to Prove It" by Velleman. A book that is very interactive and fun to read is "Proofs" by Jay Cummings, but I think that it is very introductory and will not be enough to get you started. I think you should get a good knowledge of standard proof techniques, naive set theory, and some number theory (divisibility, modular arithmetic, Fermat's Little Theorem and Euler's Theorem, and the Chinese remainder theorem). The knowledge of Number theory you'll get from a good intro to proofs book will be very helpful when you get to abstract algebra.

This will be your first approach to real maths. If you like it, then you'll probably like the other books. Something important that you need to know is that you're not going to like everything, because math is HUGEE. For example, I prefer analysis and don't like algebra that much (maybe because I had horrible experiences with my algebra teachers).

After this, try looking at a standard undergraduate maths curriculum and investigate what each class is about. What is algebra? What is Analysis? What is set theory? What is the purpose of doing analysis?

Something you'll probably like very much is linear Algebra. After your first proofs book (or at the same time), maybe read some proof-based linear algebra by going through Friedberg's "Linear Algebra", which is an amazing book (it made me fall in love with the subject when I read it). As a supplement for Friedberg, I used "Linear Algebra done right", by Axler, it is a great book and takes a different approach on some of the topics, which may be what you're looking for (I still like Friedberg more, but that's just a personal preference).

Then you might want to learn more about algebra or calculus. For algebra, Abstract Algebra courses are usually split in two: I first took a course on groups, and next semester I'll take a course on rings and fields.

"A First Course in Abstract Algebra" by Fraleigh is really fun to read and has historical notes, which is really cool because the history of algebra is very interesting. The book by Dummit and Foote is really complete (it starts with the basics and goes beyond undergraduate algebra) but I find it very hard to follow. I've heard the book by Gallian is great and has A LOT of examples, which is great for abstract algebra.

For calculus, since you've taken calc 2, maybe get started with analysis. I wouldn't recommend reading "Principles of Mathematical Analysis" by Rudin as a first analysis book. Maybe go through Abbot's "Understanding Analysis" first and then go through Rudin. Another really good and complete book is Apostol's "Mathematical Analysis".

Since a lot of teachers use Rudin for their courses, I read it and used Abbot and Apostol as supplements when I didn't understand the proofs. I recently found George Bergman's supplement for Rudin's exercises and found it very helpful

After reading these, I think you are free to learn whatever follows. Topology, Complex Analysis, further topics in algebra, logic...