As long as your plants are close to the light you can flower with fluoros you just dont get such tight buds as HPS gives you.
It sounds like you are in the same boat as me GreenB. i just got a budgeting loan for my grow lol. See if you can get a few of those 20w/100 cfls from LIDL for 99p each and put them around the sides of the plants. You could put some mylar around them if you don't already and will will probably increase your light by another 40% or so. My light used to light up the whole room until I put that mylar in now it just bounces back onto the plants and the rest of the room is almost dark. It cost me just over a tenner; Wood (roof batons B&Q £6.50) and the mylar (£1.20 mtr).
I can show you before and after pics if you like but I think you saw them already.
You should be alright today though. I' ve had some good sunshine today, how about you?
I've had some good bud too but that's another story lol puff puff pass.....