The case against suicide The case against suicide once all the emotion and man-made ethic/morality is removed, it is a matter that cannot be determined as an absolute. In other words the case against suicide is necessarily case specific and I tend to agree with the OP's attitude on this.
There are indeed circumstances where suicide is a perfectly reasonable action and other circumstances where it is incredibly harmful to those left behind. How that determination is made is up to the individual involved but since this is one decision that cannot be undone it should be made with the most complete understanding possible and that means the dreaded counseling as well as one's own research and conscience as a guide to arrive at the best choice. Suicide may be an incredibly noble and righteous choice or it may be an unbelievably cowardly and selfish choice.
I would stipulate one case and one only, if one is likely to cause significant pain to a loved one by destroying themselves, and their reason is a matter of convenience (selfishness) to themselves to avoid the drudgery of life, they should stay alive for the sake of the loved one who would be hurt. I admit this is special pleading but it's the only case I can make against suicide. Any other case that involves only the circumstances and emotions of the one who's making the choice is strictly up to them without any further qualification.
(IMO) The reason is simple enough, human emotion and feeling count for something and you will die soon enough so wait it out, life is short anyway, the wait will be relatively quick. It seems "un-natural" to cut a life short when other lives may suffer for it, other than that consideration, all bets are off and one's life is one's own to do with what they see fit. I hope you find peace in whatever decisions you ultimately make.