So I was homeschooled for most of my life, and I’m ahead in most subjects. During the late middle school years and early high schools year, I stopped caring about math. It wasn’t fun to me and I stopped trying to learn it. I went back to public school for my senior year and I’m above high school level in everything but math. I have all A’s, except for in Pre Calculus. I have a 24 composite score on the ACT, and it infuriates me to know it could be much better if it wasn’t for my math. I have a 29 in English, a 28 in reading, a 23 in science, and an 18 in math. It’s not benchmark and because of that, I have to go take the compass test. This is really depressing me and I don’t know what to do. I have a B in my pre calculus class, so it’s not like I can’t learn math. I’m just so mad at myself for wasting so many years and letting myself get behind. I don’t know what I’m going to do when I go to college. I’m almost in tears over this, any advice would be appreciated. I know this is my own fault. I just need advice on how to change my situation.
Have you tried other aids, such as Khan Academy or buying an algebra workbook at the book store? You might just be rusty. Extra time spent on problems might help you. Identify the categories of problems that you struggle with most and focus on solving those kinds of problems over and over again, as the ACT also requires speed.
Talk to your math teacher and see if they can point you to extra problems to do on Algebra/Geometry so you can get those skills back together. Get a workbook and work through it.
Go to a Mathnasium/Huntingtonlearning center type place and get assessed on what you need in math.
Look at your ACT results and see what areas you missed on Math and bone up on those.
DO NOT GIVE UP! I made a 28 with a 16 in the math and then made a 31 with a 21 in math, so I can totally relate. 33 science, 34 English, 35 reading but very poor math scores both times. In my essays I wrote about how I had basically homeschooled myself and while I knew my scores were abysmal, I felt homeschooling had taught me to be more independent, etc.Play up how you taught yourself. I have to give God credit because there’s no way this would have happened without Him- I got into every school I applied to. Baylor, SFA, TAMU, Texas Tech - and Baylor only has a 40% acceptance rate! I was accepted into their very prestigious pre-medical program. If your other scores are strong enough many schools will accept you and just have you take a remedial math over the summer. I would strongly suggest taking some dual credit courses so you can prove you can handle college work. I’m transferring 29 hours of college credit and have a 3.9 GPA in those which really helps. At Baylor, I will take two summer remedial math courses and then start freshmen year with everyone else. Don’t beat yourself up about your math scores. It is incredibly difficult to teach yourself! I wrote my own application, transcripts, calculated my own GPA, enrolled myself in dual credits, etc. While it is tough, you are able to better represent yourself than any counselor. Be real with admissions and let them know you’re on your own. Feel free to contact me with any questions! 
Best of luck in your college endeavors!