Am I just doomed to be lazy?

At the moment I'm suffering from a cold or something and paired with not sleeping well, I'm very tired and weak each day. My parents are trying their best to be supportive and ask what is distracting and what we can change to improve my sleep and my focus towards revision. I find I am very easily distracted and seeing as GCSEs are creeping up really quickly I'm feeling very doomed. I need to up my English and Maths grades in order to enter my preferred Sixth Form.
I just feel like I'm stuck in a lazy state and GCSEs being near causes a slight panic when I know I should be revising but I keep getting distracted, etc.
I just think I need my mind to be clearer for me to realise what to do in order to sort my life out. I have a big problem where my brain decides to lose thought very easily and cannot collect ideas very easily either. Usually I find myself taking forever to answer questions.
Sorry to make this so long but, my parents and teacher think I could have a type of Dyslexia and so that makes me think constantly that I have an issue and the deadline to have your GCSEs changed for extra time due to Dsylexia is in two days. My school thinks I don't have a type of Dsylexia but we don't believe that they tested every possibility and so I feel as though I am just more stupid/lazier than others around me.

Thank you for taking your time to read this, it would mean a lot if you could possibly give some advice or help as to how I could get over this or if I could do something so I am more motivated and able to work.

Also, I looked at some related discussions and most people were just saying to "just stop being lazy" and I realise how that could be easy for some, but I genuinely find it hard to change my behavior and attitude towards things. I can't say I have enough experience in life to be able to tell whether this is a phase, a personality problem or me overthinking things.

can you /your parents afford a private test?

If you've had a dyslexia test and haven't been diagnosed, then you don't have it.
You might pass a processing speed test and get extra time for that though.

Have you already been like this? If you haven't it's not a SEN, you need to see a DR.

Yes they can but it's a bit too late seeing as it's two days until the deadline...

it d still be worth it for anything you do in the future. Its better to know than always wonder.

JCQ exam rules say diagnosis after the date can be used to agree adjustments in exceptional circumstances. screen test are notorious for missing dyslexia particularly in those who have created work rounds and are good enough to use them to compensate.I would certainly find out asap as knowing can be used to adjust how your results are viewed.

Not related to the testing or anything but if you want to do the best with the hand that you've been dealt and maximise the ability of your brain and body - basically doing the best you can in the situation you're in - do a tech detox for a bit: try to lessen your phone use and computer or game use (also get a blue light blocking app for better sleep) , try to get outside exercising more often and go to the gym.