I'm searching for something I didn't read yet, I'm pretty sure it was a manhwa about an as...

this is most likely not what you're talking about,,, but there is a short animated web series, about an astronaut and it dealt with all the feelings you mentioned, It's called "Unbelievable Space Love" and it's a korean animation so its possible that its what you're talking about?? but it's not a manhwa...sorryy (╥_╥) i thought i would mention it in case;;

Thanks anyways, I'll make sure to check it out!!(●'◡'●)ﾉ