help me fill the gaps !!!!

I was translating this song to one of my friends and then I just couldn't understand some of the sentences I do know the meaning of them but I don't know how to write it down in a good way and there was a sentence or two that I just couldn't understand at all , so help meeeeeee !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Alguna vez te dije que me quedaba para siempre
did I ever tell you that I would stay forever

y lo pensé, aunque ahora quizás no te lo parezca
I didn't think so ! , but now ?????????????????

pero no hablaba por hablar
but I wasn't blabbing......... he means that he wasn't kidding when he said so


era el momento y el lugar
it was the moment and place ( the right moment and the right place )

y esta pena que siento ahora,
and this pain that I feel now

lo sé, que no me dejará igual
I know now that I don't want to ???????????


Porque, hoy es la última vez que hablo contigo
because , now is the last time to talk to you

hoy es la última vez y no puedo explicar éste final
now is the last time and I can't explain ???????????

Notas lo que te digo ahora hablas si porque me duele
?????????????????????????

creen mis ojos que alguna vez cuando nos mirabamos
believe my eyes ??????????????

pero lo dejamos pasar
but we let it go

perdimos la oportunidad
we missed the oportunity



porque hay tantos por pensar que todo lo podíamos arreglar..
because there are so much there to think that we can fix everything

This is my attempt, but bear my limited English in mind:

y lo pensé, aunque ahora quizás no te lo parezca
I didn't think so!, though now maybe you don´t see it like this
[...]
lo sé, que no me dejará igual
I know it, it will not leave me as before (nothing will be the same for me)
[...]
hoy es la última vez y no puedo explicar este final
now is the last time and I can't explain this end
No creas lo que te digo ahora, hablo así porque me duele
Don´t believe what I say you now, I speak like this because I ache

cree en mis ojos de alguna vez cuando nos mirábamos
believe in my eyes because of sometime when we looked at each other
[...]
¿Por qué? Por tontos y por pensar que todo lo podíamos arreglar..
Why? For sillies and for thinking we could fix everything