Just seen this, essbee, you poor love, what a fright!
DD2 has been having similar problems, she's always been inclined to very low blood pressure, feeling dizzy and occasionally passing out; has been to the doc once re the bleeding and got fobbed off a bit but anaemia was mentioned. As it's still happening we have decided she will go again but I will go too this time.
Anyway FWIW the GP didn't seem unduly concerned so it's presumably not that unusual; the fact that you are taking ADs probably means they should take more notice but I hope you get seen, properly dealt with and reassured this morning. XXX