Hi, does anyone know of some good doom or death/doom bands similar to the early works of Anathema, My Dying Bride, and Paradise Lost? I like a little bit of the gothic feel, but I'm looking for something a bit heavier.

Mourning Beloveth sound like the continuation of the Crestfallen EP by Anathema hadn't they started changing their sound early on. Avoid their third album.

Try Cryptal Darkness for something similar to early My Dying Bride, Martin Powell played violins with them which makes them quite similar.
Dissolving of Prodigy is another good choice for some good My Dying Bride worship.

You might like Novembers Doom. I personally don't, but the similarities are there.

Doom VS , also Winter well maybe not winter but they are the greatest doom band ever

Try Requiem - Fortissimo by Virgin Black, its a death-doom album inspired by the early music of Anathema, MDB and Paradise Lost.