Ever since my last relationship where I caught my girlfriend messaging 10 other guys behind my back I've found it really hard to smile. I know that probably sounds weird but I've done Yoga and meditation and to a certain degree I feel probably 80% at peace. The other 20% is the niggling heartbreak that just won't leave me alone and sometimes manifests as nightmares and panic attacks through the night.

Anyway generally I feel like my mind is peaceful enough not to think about what she done and the past but every time someone smiles at me I feel like I'm really making physical effort to try and smile back, it feels foreign. It almost feels like I'm fighting myself to do it and I can't understand why. In past if someone smiled at me it would be infectious and I would smile back, now I feel like I consciously have to force one out of politeness so I don't look rude or get concerned questions.

Has anyone gone through this before? Is it just a time heals wounds kind of thing? Will it come back again?