Draconian is an excellent gothic/doom band and are one of my personal favourites. Their music is very melancholic and dark, as one might expect and not be listened to when depressed.
Samples:
Not Breathing
https://www.youtube.com/watch?v=4k_INmy2OGI
Seasons Apart
https://www.youtube.com/watch?v=WPqy56fetjs
Bloodflower
https://www.youtube.com/watch?v=uijqBrAdhy0