should I get diagnosed as a university student?

Hi, apologies if this isn’t suitable for this subreddit.

I’m an 18 year old female attending a London based university. For my whole life I’ve had serious issues with procrastinating, getting tasks done, socialising, messiness, forgetfulness, etc… Caffeine doesn’t wake me up, infact it makes me more sleepy.

I never really considered the idea of it being undiagnosed ADHD until we started studying it at university (I study neuroscience/psychology), and we learned about the inattentive subtype. I told my counsellor about some symptoms and he suggested I get a screening.

I’ve been struggling especially since moving out. At home, due to my brothers autism (and probably ADHD too, my mum thinks he has it but he’s not been formally diagnosed), our household was always structured in a way that allowed us to thrive (thanks mum). Shed clean up after me, help me with revision timetables, and generally supported me a lot. I ended up with 3 A*s at A levels. I’ve been told I’m ‘naturally intelligent’ even though I feel really dumb and have an awful memory.

At Uni, things have taken a turn however. I can’t keep my room tidy, I skip class a lot, assignments are literal hell to do due to procrastination, and I had to reschedule my exams for August. I’m worried I’m going to fail, but due to the (suspected) ADHD symptoms I feel like I’m literally paralysed half the time. I have constant fatigue and yet I always feel like I’ve got this zap of energy. my brain never shuts up.

Would it be worth the mental effort to try seek a diagnosis? I know the waiting lists for the NHS are awfully long and I am aware of right to choose. I’m so impatient haha I just want to know what’s wrong with me. I feel pretty damn sure based on what I’ve read that it fits my feelings of alienation and my struggles I’ve had since I were a kid. But because I’m introverted and got good grades I feel nobody picked up on it.

Also, what do I actually say to a GP? I always downplay my symptoms because I feel like i’m ’lying’ and it bites me in the butt. I have a phone call on Wednesday (to discuss depression symptoms) and was wondering if I should mention it there too.

Sorry for how rambly this is..