There arent words to describe how I can possibly thank my beautiful friend Francia Raisa, Gomez wrote onInstagram.

She gave me the ultimate gift and sacrifice by donating her kidney to me.

On Monday, Raisa opened up onHarryabout her experience and recovery.

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So trying to recover from that, and [Gomez was] gaining something her body needed.

So shes up and at it immediately and I had a hard time.

Two months, I couldnt do anything active.

All I could do was walk.

It was really, really hard.

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Donating a kidney certainly isn’t easy.

People with diabetes, high BMIs, or organ diseasesmay not be able to donate.

Donors are usually out of the hospital in one to two daysthe next day in our program.

That doesnt mean you have your kidney removed and you wake up feeling amazing.

Its still an operation, Dr. Rajab says.

These donors are coming into the hospital as completely healthy, normal people.

Theyre going to wake up with an incision, pain, and having had anesthesia.

However, within a few days, donors often start to feel bettertheyre just not 100 percent yet.

“It has to work doubly hard,” he says.

Most centers will want you up and walking around while youre still in the hospital after your surgery.

The only thing we dont want them to do is heavy activity, Dr. Rajab says.

No push-ups, sit-ups, or weight lifting for anywhere from four to six weeks.

(You have internal sutures that need to heal, Dr. Friedewald explains.)

By six weeks, you should feel like yourself again.

There is a risk for some rare complications, such as aUTIor other infection.

And after the six week period, youre generally OK to do whatever you want.

We tell people that after theyre healed, there are no limitations on activity, Dr. Friedewald says.

Kidney donation is a serious decision, and transplant centers generally advise people to wait before making anything final.

But Dr. Rajab says hes in awe of people who decide to help save a life this way.

Those people, I have great admiration for, he says.

They are a really different throw in of people.