Hi Becky
Thanks for taking the plunge and posting your lyric
It's a very personal lyric which always makes it hard to critique because it's so personal to you, but these are my immediate thoughts.
Best line : Now I have you I'm so unprepared
Such a shame that the previous line is 'running scared' - there's nothing wrong with this phrase except that it's been used far too many times by others. I also think it would be easy to change without losing any of the feel of the song.
The second line of the chorus doesn't quite sound right to me - 'send my head into a spin' makes more sense but I realise this may not fit with your phrasing and melody.
On the whole, very honest and raw, and brave. Keep writing, and feel free to share any recordings you may have with us