First, did you ever submit a FAFSA with the correct numbers or are the colleges still working from estimates? An accurate FAFSA might change your financial profile.
So UCONN offered you nothing in the way of financial aid, correct?
I looked on line and it appears that tuition, fees, room, board, books is about 27K. If you took a federal student loan of 5.5 K, that would bring it down to about 21.5K. Part-time and summer work could probably get it down to your dad’s number of 18K. So if you are willing to assume personal debt (maximum allowed for the four years is about 27K), it “might” work.
Are you able to commute to UCONN? That would reduce the cost for tuition, fees and books to a little over 14K. If not, would it be cheaper to live off campus in a shared apartment than on campus? I know that cost of living in CT is not cheap but you might be able to shave a few thousand dollars off the room and board costs by getting an apartment nearby and doing your own cooking.
Unfortunately, many state flagships in the NE corridor come in at 25-30K for state residents. It’s the going rate in a relatively high cost-of-living area.
Also, as your siblings enter college, your EFC as a family will be recalculated to reflect the additional costs to your father.
To reiterate what others have said - if none of your current options are affordable you could take a gap year and apply to places where your academic profile might get you some merit-based aid (Clark U in Massachusetts comes to mind). Also look at OOS options that offer merit money for your stats. This would involve expanding your geographical parameters a bit:
http://automaticfulltuition.yolasite.com/
If you nudged your SAT up a little bit more, there would be even more options.
Or you could do CC for two years and then transfer to UCONN or another CT state campus.