i can only hazzard a guess to what went on between u both as i have been in a similar position
ive been depressed for many many yrs and the severity has fluctuated within that depression
im aware that at times its hard to really hear what ppl say to you and to see how they feel and how they are ultimately affected by ourselves being unwell
its important to be able to acknowledge this
that even thou depression makes us selfish we still need to as much as possible stop thinking that their motives are to hurt and destroy you/us
there is alot more behind ppls actions that are as severe as these ones
and yes u may need to say good bye to this friend forever
and you may dwell on the whole situation
and you asked whether they had been planning it and yeah u may have missed cues as to something being wrong in this
just as in a similiar situation i had where lines where blurred as to what was appropriate to discuss with certain ppl and what the friendship was all about
once again when in such a depressive state its gonna be hard to see past ur nose to realize whats going on with the world around you
and i dont say this to be mean and nasty i say this as honestly as i can relaying how at times its been for me in my life and from what i know about depression
the biggest thing that i learnt from everything i went thru and am going thru is that although depression is selfish and generally bad selfish there is a good selfish part to each person in standing up and helping themselves
i was blessed in an unfortunate way i guess in that i had no friends initially to lean upon or find support in i was completely alone seeking support from doctors and other clinicians but that was good bcos the strength that i have from that meant i wasnt needing to rely on friends heavily and was able to maintain friendships as it wasnt all about my depression as it wasnt until many yrs after meeting them and im talking about like 6yrs for one of my closest bestest friends b4 she knew the truth.
im not saying this is u once again drawing on my own experience to try n help u out.
good luck with ur healing process
dont give up