Having trouble breathing..

Hey everyone,
I posted here not long ago about my SVT's increasing..

But the reason i am posting now is because yesterday throughout the day i felt really dizzy and like i couldn't get enough oxygen in and starting feeling tingly in my arms and legs.. i went home and went to bed because i was exhausted (chronic pain not from breathing problem) i slept for about an hour but woke up feeling sick and just uncomfortable, my arms felt really weird and my chest felt weird but i can't describe it.. not painful or tight just really uncomfortable.. i felt like i wasn't getting enough oxygen in and when i tried to take deep breaths my lung capacity didn't feel right.. normally i can get so much air in but this time i could hardly get any in before it stopped.. i just had to keep focusing on my breathing but then when i went to bed last night i kept waking up and realising i could breath properly/had just stopped breathing. i felt reeeally uncomfortable then and sick and just not getting enough oxygen and couldn't and my chest was feeling tight.. i told my mum but she said there was nothing we could do and it was probably just coz my lymph nodes are really swollen.. but this feels like its in my lungs more.. its still happening and making me feel sick and it just doesnt feel right.. and unless im thinking about it i forget to breath.. like its not a normal reflex. even while typing this i am holding my breath without noticing because i think because its hard to breath i just stop unless i'm telling myself to..

does anyone know what this could be? i don't think its anxiety because i really am a pretty laid back person and dont feel stressed or anxious about anything at the moment.. and the fact that its not coz im worried about something making it tight but that even in my sleep i stop and i just stop when im watching a movie or typing etc..

Its making me feel pretty rank and tired so wouldn't mind any suggestions :)

Thanks heaps