Your breasts will change considerably in the first four months, so you still can expect this to improve. That said, your implants appear a bit high, so I would recommend following up with your PS. There are a couple things you can do to help such as wearing a breast band to help apply downward pressure to the implants, or you can manually try to push the implants down and stretch the bottom portion of the capsule to help it settle. Do this by making a fist with your right hand, placing it on the top portion of your left implant, and using your left hand to press your fist into your chest. Done properly, you should feel a stretch on the bottom portion of the implant and breast. Do this for the left breast, then reverse, and do for right breast a couple times a day for several minutes. This should help a little. As far as size, I would guess from your photos that 350 would give you a middle to full C, so hang in there.
Implants Need Time to Settle
Based on your before and after photos, I do think 350 was a good size selection.
Your implants are high, but should settle over the next few months.
Go see your surgeon, share your concerns... I am sure he/she will reassure you.
Your implants are very high, but this should correct itselft in time, its much too early to be concerned as your results wont finalize for another 4-5 months. In your photos you look dramatically different and the size is probably a great choice for you.
Give it time, you'll be surprised how much they will change.
Unhappy with breast enlargement size
You should have been given an implant identification card after surgery. It will tell you the size of implant that as placed. Chances are it is a 350 cc implant. Your implants are under the muscle, the muscle is in spasm and until it relaxes, the implants will stay high. You actually look very different compared to before your surgery - but the implants at the moment fill out the upper chest. As they settle - the look will improve. In rare cases, implants do not settle and additional surgery is needed but this is very uncommon. Best wishes.
350 cc breast implants need to drop further as they are high on your chest
The fact that your breast implants have not dropped down beneath your nipple areola is making them look high and small. I do not doubt that you have 350 cc breast implants is just that they are not in the proper position.
Typically I would wait 3-4 months to allow the implants to drop, I would encourage displacement exercises, and I would have you wearing a superior pole wrap in an attempt to force the implants down. If after 3-4 months the implants are still high a simple release procedure could be done to drop them.
Your implants are sitting high on the chest wall. Often surgeons use stitches at the inframammary fold to ensure that the implants dont drop and cause a problem later on called bottoming out. These stitches can be permanent or dissolvable. Dissolvable stitches usually cause relaxation and drop of the implant between 1-2 months.
The control of the inframammary fold with stitches can cause implants to sit high initially. Almost always breast implants drop and your implant volume is currently sitting in the upper pole rather than in the lower pole. When the implant drops you will hopefully achieve the result you are looking for. You may wish to see your PS and explain your concerns and gain further reassurance.