I also make something similar...

1 package of s/f jello...raspberry or lemon
I cup heavy whip cream whipped
4 oz cream cheese
1 cup frozen berries, or 1/4 cup lemon juice(used with lemon jello)
1/2 cup splenda

Whip cream to almost thick. Add cream cheese then blend until real thick. Add 1 cup hot water to jello...add frozen berries to cool the mixture. add to whipped cream mixture...or add lemon juice to hot mixture...wait about 15 mins for it to cool then add to whipped mixture. Blend on low for a min or 2 so that it is all blended well...put in fridge...ready in about 1 1/2 hours...the whole family loves it when I make this...and it is delightful. NOTE: When I make it with the lemon, I usually add 8 oz of cream cheese. Then it tastes like cheese cake.