Could ADHD be a possibility for me?

Am new here, have been posting in the BPD, NPD, bipolar etc forums, getting myself all confused and thinking too much - trying to make a list of my behaviours and symptoms etc. i have a psych appt soon, was referred as there were several traits that couldnt be diagonsed properly at the time.
for a while now ive noticed these problems getting a lot worse - concentration and distraction. I cant focus or concentrate on anything for very long unless it is fun and interests me. as a result my school work has gone epically downhill - i have chemistry a -level exam tomorrow and i havent really started studying for it yet! because i look for other things to do instead, procrastinate...and when i do try to study, i just get distracted by things and then never come back to it.
i get really irritated a lot.
i switch off when people are talking to me and they find it really rude but my mind just wanders off and i start thinking about other things, all to do with myself.
i sometime feel like i have loadsa energy and want to use it - i hate being stuck indoors it feels like prison - if ive got sumthing boring to do like revision i'll even just go and sit outside so im outside. want to be doing fun things all the time. I posted in the BPD forum on sat night because i was panicking about being alone - i cant bear to be at home bored when other people are out having fun, i wanted social stimulation etc.
i crave and desire attention.
i talk excessively to certain people i feel comfortable with, like my brother
i butt in/interuupt their conversations
- and i always have done..my mum told me when i was younger, whenever she was tlaking to someone id say ''mummy, mummy ,mummy,mummy' etc
until shed stop the convo and ask me what i wanted to say and then id say 'nothing' i find myself doing this now often...i cant wait to say things sometimes
i also noticed i sometimes finish the sentences or talk over people-especially when im at an appt like at the doctors...i went with OCD probs and he mentioned cognitive behavioural therapy and i remember the doc couldnt remember what it was called and i said it before him/at same time.
i cant finiih anything i start

and i just went on this forum for the first time a few mins ago and read the diagnostic criterea and pretty much ALL of the INATTENTION ones sound like me..and i thought ''oh my god!'' - im not the stereotypical hyperactive kid at school or anything and people would never think id have ADHD but a lot of the symptoms just sound so much like me....like at school im VERY quiet...but sometimes ill be sort of buzzing inside and WANT to do things, but im too shy/reserved to.

Can anyone give me their opinion on this? Thanks :]

and racing thoughts!