Regression or normal?

We've now entered out 12th week out of nappies and using the toilet and I really thought it would have been plain sailing by now, but I don't feel as if we've progressed much in the last 10 weeks and I don't know why....

We started accidentally when MissG was 25 months old as we left her to it one morning and she used the potty all by herself on several occasions. From there we followed Gina Fords 1 week plan and it all really did go well.

She's managed to string together a whole seven days of being dry and clean at around the 4th week.  Since then, she's never gone more than 4 days without an accident.

For the last couple of weeks it's been pretty much daily, sometimes with more than 1 in a day.  Yesterday was our worst day yet with 3 in a row and not a bit of effort made to reach the toilet.

I'm worried we've gone wrong somewhere and I don't know how to fix it.  She seems to be getting worse instead of better. I've tried out a few reward systems, but none seem to be incentive enough for her to go long term without accidents.

The number of pees in the toilet far out number the accidents, but surely after 12 weeks, she should be able to go longer between accidents?!?!

Am I expecting too much?  How many and how frequent should normal accidents be at this age?  I know to expect accidents on occasion up until 3 yrs, but what would you normalize as 'frequent' and 'occasional'.

I feel like I'm constantly hounding her about using the toilet - it's just a constant background siren in my life right now and I really thought that by this stage it would be easier.

Any advice?