It's been some time since I took a-levels, but I remember the feeling of overwhelm associated with them. Is there anyone you can reach out to and talk to at school/college? Or is there anyone at home or a trusted family friend?
First thing to remember is that you do have time to prepare and anything you do now will help.
Do you have a revision timetable drawn up? If not, then you could ask someone in pastoral support or a nice tutor to help you with this.
When you say you are struggling with homework, have your tutors given you feedback? If not, ask for it and try to identify the areas you need to sit down and try to work on understanding.
It is expected that you may feel at information overload, a levels are very tough. Do remember that you need to ensure you are giving yourself some time out through the week. It is essential for your brain to have some genuine times of rest and time to digest the information you are learning. So for me, I would set out Saturday as my day just for me. I would make it clear to myself that I don't study or work on that day. If you can't do the full day, then set out half a day. Get outside in some sunshine, at some nice food, watch tv you enjoy, spend time with your friends and family or pets if you have them. Anything to give yourself some time away.
Then regarding your revision and homework time, work out when you need to do homework and then what evenings would work well for revision. Try different techniques to keep yourself interested. So I would use visual cards to break up concepts into chunks and I could look at them every now and again to test myself. I would also record myself on my phone on voice recorder talking through a concept that I needed to remember. I would record it in such a way to ask myself a question and leave a gap, before giving the answer. You can then go back as many times as you like to relisten.
Another thing I found helpful was using a small whiteboard. For maths, you could practice equations in that and test yourself. Practice the areas in your homework where you aren't getting the right answer.
But mostly importantly, please reach out to people in your college or school to ask for help. There are options available to you and support. Many schools and colleges also offer homework help and additional study support. I wish you all the best with your studies.