Yes, I think it's perfectly fine to still be feeling this way. It's like he died and you're grieving his death, but in this case, it's the death of your relationship with him and who you thought he was. The winter months and the holidays are definitely not helping. Keep doing what you're doing, don't punish yourself for feeling the way you are, and keep taking care of yourself. Soon enough, spring will be here, and I'm sure you'll start to feel better. In the meantime, treat yourself like your best friend... What would you tell them in this case?