My girlfriend recently mentioned a girl at her work whom she thought 'had a nice body' and was overall 'hot'. Now my girlfriend compliments a lot of people, it used to irk me so bad but now I am at a stage (sometimes) where I am okay with who I am and it doesn't bother me as much. I still have my down days where I think I am scum of the Earth and we both have plans in place to help me through there dark patches and so far so good. 
My problem is - this other girl is actually gorgeous. Like, in my eyes, for some be known reason I instantly class her as a threat even though this girl herself and my girlfriend have both said nothing is happened and nothing ever will happen. But me being me, I created a situation in my head where they will run away together, or sleep together at work or just plain crazy stuff that I know is crazy once I shift my mindset out of that 'phase'. But I can't stop online stalking this girl! And part of me wants to be like her, I want to get my hair braided like she does and I want to lose weight and tone up like she is etc etc it's literally driving me insane like I try to block her on social media's but I end up unblocking her and stalking her and either way looking at her profile or having her blocked drives me crazy... Any helpful advice to help me 'get over' this phase? 