As a "straight 9" student myself, I definitely agree with the statement above. I feel like for the majority of students, the struggle is just dealing with procrastination and getting things done. Look at what you do in a day and say to yourself, "what distracts me?" and "what is getting in the way of me studying?" If it's things like Netflix or Youtube (which I'm very susceptible too dw), try and remove your phone or laptop from your desk, give it to a parent, do something that will really help change your environment so that you'll focus and just get on with it. If home is too busy, you could even go to a library. I find that rlly helps me concentrate cos my family is quite all over the place
Another way I revised was using the "Rule of 8". You have 24 hours in a day, leave 8 hours for sleep, 8 hours for free-time and 8 hours for work. 8 hours a day of study is enough time from now until your GCSEs to revise and get work done. Of course, this won't always be the case, but at least try and manage your time in this way, so you have something better to work with. And then divide your 8 hours of work into, let's say, 30 mins revision on a topic and another 30 mins on past papers. Take a break, and then press on with another subject etc. etc. Use those hours to then make flash cards, make good notes and go over your specification. And as you would've heard a million times already, do practice papers (preferably in timed conditions!)
I understand GCSEs can be stressful as you have to balance such a large number of subjects, but it's certainly doable. And anyone can achieve the grades if they are consistent and know how to manage their time. Just take things one at a time, and obviously, don't tire yourself out. Even though mocks may have not gone the way you wanted them to go, you can still utilise the time you have to prepare for the actual exams. I got a 5 in chemistry and biology mocks, but ended up getting 9s in both at GCSE, so you can do it. Have faith in yourself, I have faith in you too!
The smartest person in the world could give you the most amazing tips on how to revise and how to achieve the highest grades, but it's evidently up to you to discipline yourself and actually do it! Anyways, if you have anymore questions, feel free to ask. I hope at least something from this was helpful lol. And good luck!