Sounds like Bottoming Out
There are many sensations that can be normal after breast augmentation, but the ones you describe sure do sound like at least a little bit of bottoming out. If it is, your photos do not look that bad. However, sometimes there can be only a little bottoming out on the bottom, but more stretch (or lateral drift) to the side, making the space between the implants much more, or give a sensation of heaviness to that side and sometimes stitches a nerve giving discomfort. A bra may help with the sensation or discomfort but is unlikely to "fix" the problem. Depending on what is actually going on, you may want, or need a tightening of the pocket (capsuloraphy), or if it is not that bad, the bra may be the ticket.
Early bottoming out of implant
One of the earliest symptoms I have noticed in our patients who develop a bottomed out implant is exactly what you describe as a "heaviness" to that side. In my experience, an underwire bra worn during the day may help keep this in check and prevent it from going further downward work would then have to be repaired. Follow up with your plastic surgeon about their thoughts on the subject is recommended.