Double bubble correction needed? (Photo)

I would recommend transitioning to a vertical lift. This will correct your breast shape and give you a nicer cleavage since the implants will be higher and closer together without needing to change the implants.

Dear Vivid736629,
though rare, some women who undergo breast augmentation will develop a minor deformity known as a “double bubble,” in which additional folds appear underneath the breasts due to the implant accidentally shifting or contracting post-surgery. In most cases, the implant simply slipped too far down the chest wall and traveled behind the breast inframammary crease (the area where the lower breast meets the chest), instead of moving forward to fill the breast cavity. If left untreated, the lopsided implant will form unnatural indentations, resulting in an odd “four-breast effect” rather than the full, rounded chest the patient initially desired.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery

Don't go larger or you will just sag again. Your folds need to be lifted and tightened again and you may need mesh. Going smaller with lighter implants would be helpful.