Lydia is not responding to any of my commands, when i tell he to follow me she says ok then simply stays where she is, i have repeatedly asked her to follow me but to no avail. I wouldnt usually care but this is preventing me from doing the dawnguard quests so yeah. Any suggestions?

I left Lydia in my house for 3 days once and she left me. When I saw her again on the road she would hardly talk with me and I could not get all the cool gear I gave her back.

My first heart break in Skyrim.

I would load up an older save and see if she will talk to you. You might have a bad save.

She might be stuck (even if it's not apparent), did you try going through a door or other loading screen to see if she appears behind you?

Try those in your console:

a2c94.disable

a2c94.enable

Did you use the placeatme console command on Lydia by any chance ?