Short answer. Yes to both. Section 11 of Rule 67 says that once the appellate court determines the plaintiff has no right of expropriation, the trial court must forthwith enforce restoration of the property to you and determine the damages you sustained and may recover because of the possession the plaintiff took.
What the law says
The right of the plaintiff to enter upon the property of the defendant and appropriate the same for public use or purpose shall not be delayed by an appeal from the judgment.
Rule 67, Section 11 — Entry not delayed by appeal; effect of reversal. Read the full provision →
What the law says
if the appellate court determines that plaintiff has no right of expropriation, judgment shall be rendered ordering the Regional Trial Court to forthwith enforce the restoration to the defendant of the possession of the property, and to determine the damages which the defendant sustained and may recover by reason of the possession taken by the plaintiff
Rule 67, Section 11 — Entry not delayed by appeal; effect of reversal. Read the full provision →
Why the government could take possession before your appeal was even decided
Section 11 explains why the possession you are describing happened at all while the case was still being litigated. The right of the plaintiff to enter upon the property of the defendant and appropriate the same for public use or purpose shall not be delayed by an appeal from the judgment. An appeal does not pause the government's ability to take and use the property, which is why possession can already be underway when the appellate court rules.
What happens once the appellate court reverses
Section 11 addresses exactly your scenario directly. If the appellate court determines that plaintiff has no right of expropriation, judgment shall be rendered ordering the Regional Trial Court to forthwith enforce the restoration to the defendant of the possession of the property, and to determine the damages which the defendant sustained and may recover by reason of the possession taken by the plaintiff. A finding that there was no right to expropriate triggers both consequences you asked about, in the same provision.
Restoration of possession is ordered immediately
The trial court is directed to enforce restoration of possession forthwith once the appellate court's reversal comes down. That word signals the trial court is not meant to sit on the matter or wait for further proceedings before returning the property to you — restoring your possession is the first, prompt step required once the reversal is final, ahead of the separate work of computing what you are owed in damages.
Damages are determined, not assumed at a fixed amount
Getting the land back is not the whole remedy — the same provision directs the trial court to determine the damages you sustained and may recover because of the possession the plaintiff took. That determination is a separate step the trial court must carry out on the facts of your case; the rule establishes your right to recover damages for the possession, without fixing what that amount is in advance.