Hey Blackbird.
I do not have the opposition, but I do have the conjunction between these two 'planets.'
I think where Neptune is involved, it doesn't necessarily matter what the hard aspect is. It behaves pretty much the same way, in that it creates similar similarities.
Moon/Neptune natives tend to have 'missing mothers' in some sense of the word. For you, she moved, but stayed in the picture in the most remote manner. For me, she literally just up and left. Awww, thanks conjunction, lol!
That's not to say that I didn't have a mother figure. I did, though she was overly protective and shielded me from the world leaving me very, very naive and with no boundaries whatsoever.
I was never sure when it was appropriate to say no and when it was 'wrong' to do so. She had my life so planned out for me that I had trouble
deciding which clothes to wear once I was 18; which was unfortunate since the age of 18 is when my parents threw me to the world and withdrew all support. Oh my word......
Anyway, I digress.
At several points in my life when I was younger (especially before the age of 25) I felt suicidal. I tried a couple of times and this is the first time that I have ever shared that publicly. I just want you to know, even if you don't understand that it does get better. Much, much better. The trick is to set your desire, goal, focus, intention and will towards not escaping but creating, earning and developing the tools to move through this period. Spend time with yourself, just you. Get to know and delight in all of the beautiful little idiosyncrasies that make you so incredibly YOU. Nurture those things and set your will (even if it takes practice).
It's wasn't 'easy' for me, but it was very illuminating and helped me understand that each aspect is a PROMISE of a beautiful potential. Trines are beautiful until they create boring, slothful folks who contribute nothing and squares are horrible until they shape the majestic individual's in complete command of themselves.
I am not saying that your trip is anything like mine. Indeed, our two realities may only intersect here, online; but still maybe just knowing that you are not a single voice in the night, so to speak may help.