Harsh as this will sound, whilst you feel you are at best, treading water, what you're actually doing is going backwards and if you're in the circuit, you're becoming institutionalised to the circuit which will cause problems when you leave.
As an instructor for over 4yrs, my advice (as I've seen this again & again) is to break-off until the funds are there.
What you're doing is really just a series of trial lessons for someone who can just about circuit the aircraft.
Its one of the worst places to stall in your progress ( only nav is more expensive).
It doesn't take much, if you're in the circuit, I'd budget getting yourself solo again in around 5-10hrs. Sounds a lot, but since you've stopped your regular flying, how many have you already knocked up without progress? Going solo is about reaching a peak, getting pushed of the edge (the instructor saying " ok, make this one a land, I'm getting out!!) and then consolidation afterwards.
As such, your flying needs to ramp UP, not just bounce along
Bb