Hi Rachel
I had the exact same, positive lumbar puncture but negative CTs. I didn't have an MRI or the scan where they send dye through your groin, because of my pregnancy (radiation risks to baby).
I didn't receive any treatment, because there is no treatment for an un-identified bleed. I was discharged home and advised to rest. I was told that it was likely a venous bleed that was small and therefore didn't show up on CT. I was discharged and left very confused as to whether or not I had suffered an SAH.
The wishy washy diagnosis has since worked in my favour, no driving restrictions, its not written down anywhere that it was a confirmed SAH, just suspected and then not treated for, which helps for things like insurance.
After about 6 weeks, my headaches stopped and I felt much better.
I will be reviewed later in the year.
I hope you feel better soon.
X