Caravan sitting low at the back

I'm a novice cvaravanner and have a lovely 'classic' Abi Marauder.  I;ve done the clubs introduction to towing course and know the van should sit forward, dipping towards the towbar, however on or 1st outing our van just wouldn't do this.  We packed it as stated, heavy items forward and low but nothing seemed to help.  Our towcar is a Vauxhall Meriva (I know, don't laugh!!)  Any ideas anyone?  We're off over Easter and I want to feel confident towing.  We didn't have a stabiliser for our 1st outing but have one now, would this make a difference?