Saline implant shells - moved/travelled in my body? Terrified

I wouldn't be overly concerns. The implant shell is likely still in the capsule. If it's deflated and you have adequate breast volume it may just be hard to feel. There's no way for it to migrate outside the capsule.
Although not an immediate health risk it is recommended to have them removed. The capsule (the scar tissue around the implant) tends to shrink down to the size of the implant.

Hope that helps!

Dear Timberoni,
if you have implant shells left inside the breasts, then they should be removed. They are located inside the implant pocket. They can't move to other body parts. Ultrasound should show their exact location.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery

I’m sure the shells are still in the pockets because the pocket tends to walk off the implant shell. Consider an MRI if you want confirmation

The empty bags are still present behind your breasts, but may be wadded up. There is no reason to be terrified because your body will treat them the same whether they are filled or empty. The ultrasound will show where they are. Sometimes you can feel the points of the empty bags.

Never leave an empty silicon implant shell in position. This can cause other problems. Best to have them removed immediately. But ultrasound is advisable. Expect me to range from $5000-$10,000. Best to virtual consult with.