Without a photograph it is impossible to specifically answer your question except in generalities.
The vast majority of patients do NOT have loose tummy skin after a well performed tummy tuck (Abdominoplasty). From your history of 3 C-sections (last one by vertical incision (?reason), I think your choosing to have a mini-tummy tuck was ill advised and is the reason for this result.
Not all Tummy Tuck procedure are applicable much less produce equivalent results in all women. Consider the reasons for a second. With the massive extension and stretching of the abdomen in EACH pregnancy (much more so with 3), the abdominal wall muscles and their connections are stretched resulting in a larger abdominal cavity AND a separation (diastasis) of the rectus (six pack) muscles which cannot be restored by anything except surgery. The overlying skin, everything from the rib margins above to the rim of the hips and pelvis below is stretched until it resembles a spinning top. After delivery, there is SOME shrinkage of the skin but you are left with a pooch / overhang related to the excesses of abdominal wall laxity.
To restore your figure to the BEFORE-pregnancy look, each one of these components must be corrected. A Mini-tummy tuck removes skin excess below the belly button (leaving excess skin above) AND repairs the muscle separation below the belly button ONLY leaving the separation above and stretched out abdominal wall uncorrected.
While the mini-tummy tuck may be acceptable in a woman without muscle separation and minimal loose skin confined to below the belly button, it is really a rather poor choice for someone with your clinical presentation.
You can read much more about TUMMY TUCK and MOMMY MAKEOVER at the comprehensive link below -
Dr. P. Aldea