Why am i loosing and gaining weight like this?

I gained a lot of weight from having children 1st preg went from 95 to 150 then lost 10 lbs to stay at 140 2nd pregnancy went 140 lbs to 170 lbs then got down to 140 lbs again. 3rd pregnancy did 140 to 170 lbs again but then went down to 125 lbs. 4th preg went to 175 lbs and afterwards stayed at 170 lbs. I went on atkins and in 3 mos went from 170 to 140. Now I went off atkins i can eat anything all day i dont gain anything but if i want to loose any weight at all i either have to go on a liquid or atkins diet why is this is something wrong with my metabolism by the way im 5 ft 1 and i would like to get down to 110 lbs.