I have Sientra Breast Implants 350cc, went from 34a to 34d. Am I Bottoming out or getting double bubble? (photos)

The implants are not bottoming out.  Your implants appear to be well placed, the surgeon probably had to lower your inframammary crease to center the implants and make sure the areola was centered, this does create a double-bubble, but this will stretch over time.

Your post-operative pictures suggest the presence of a
persistent inframammary fold and a mild double bubble deformity.This is not uncommon when the distance from
the areola to the new inframammary fold is increased to accommodate a larger
breast implant.Under these
circumstances, it’s not unusual for patients to feel their breast implants
beneath the level of the old inframammary fold especially if they’re thin and
have minimal breast tissue.In the
vast majority of patients, this problem improves with the passage of time.Under these circumstances, the weight of the
implant stretches and expands the soft tissue.If this problem persist beyond six months, revisional surgery may be
necessary. It’s
important to discuss these issues with your plastic surgeon. Your surgeon
should be able to formulate a treatment plan that addresses your concerns.

Your previous inframammary crease is still barely visible, but causes the double bubble appearance you see on your left breast. However, your nipple-crease distances appear to be symmetrical and well-placed.BTW, you had cohesive silicone gel implants, but the original "gummy bear" implants were the McGhan (Allergan) style 410 shaped, textured, cohesive gel implants. These are now FDA approved, but when they were in FDA studies, they acquired the lay public and media nickname "gummy bear" implants. All of the other silicone gel implants by all 3 USA implant manufacturers are also cohesive, but are typically somewhat softer, less rubbery, and slightly more natural in feel. Since all silicone gel implants are now (some degree of) cohesive, many surgeons and even more patients describe the latest generation of cohesive gel implants as "gummy bear" implants. Technically incorrect, yet still a different kind of cohesive similar to the true gummy bear style 410s.If your Sientra implants are textured, you have very little worry that they will drop too far, since the texture is designed to adhere to your tissue capsule. That scar capsule will mature, soften, and stretch over time, as will your skin, so this slight double bubble may well resolve over time. An elastic bandeau may help; ask your surgeon.Revision is unlikely to be necessary, but it will take a full 6-12 months to answer that definitively. I actually think you look pretty good (for what I assume your pre-op anatomy to have been) at this point in your recovery. Be patient and glad that you chose a good surgeon! Best wishes! Dr. Tholen