Hi mideastprincess,
I would probably try your mattress on the floor for a while (a week or so) and see if that solves the problem. If it does then that and the fact that sleeping over the part of your slat bed that doesn’t flex would seem to indicate that the flexible slats are the issue and is allowing you to sink down too far with the heavier parts of your body (the pelvic area). This would also tell you whether it was your mattress or the flexible slats that was causing the problem.
I don’t know the details of your slat bed so I don’t know what kind of changes are possible but if it appears that the flexible slats are the problem and you can exchange the flexible slats for non flexing rigid slats then the odds are good that this would solve your problem. If the slats cant be changed for some reason then removing them completely as you suggested and replacing them with a firm non flexing frame something like this inside your bedframe (or one of the others that are linked in the foundation thread here) would also have good odds of success.
Phoenix