iPhone 5 won't start after ios 9.3 update - help!

hi everyone, this is the first time I have used this forum so please bear with me

I clicked on the update on my phone, the whole thing went dead so i tried to both update then restore via my itunes, which didnt work at all, and now my phone is telling me to connect to itunes but my itunes doesnt even find my phone - there is no device showing.. I'm at my wits end as I really need my phone!

Thanks for any help