I had my implants changed out for larger one 8 years ago. Are my implants bottoming out? (Photo)

Yes, you are bottoming out from the weight of the implants. After pregnancy, your breast tissue was stretched and thinned and no longer is supporting the weight of your implants. Ideally, the inferior pockets would be tightened, use mesh for support, and you would go down in size to help maintain the position better. Your tissue may not be able to support the weight of these implant even with pocket tightening and mesh.

Dear Ledena,
based on your photo, it looks like implants are placed low. Bottoming out occurs when the implant falls below the current breast crease or inframammary line. It's more likely to happen with inframammary incisions, which is why I try not to use the inframammary approach to any breast surgery.
Bottoming out can also occur if an implant is too large for the breast pocket. That is why it is important to choose an implant size that's correct for your body. I perform numerous measurements in the office to determine optimal implant size for my patient's bodies.
If you are concerned, please check it with your plastic surgeon for reassurance and to further discuss your options and possibility of revision.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery