Help!! My kumquat tree is losing it’s leaves, even the healthy ones!

I have gotten it as a graduation gift a month ago and it was perfectly fine, then I was keeping it on my balcony, but I moved it inside for a week due to strong winds and since then its leaves started drying and falling. Now I decided to put it back outside because the weather is nice again, but the healthy leaves are falling now as well.

I water it once every two weeks and it gets a lot of sunlight also direct sunlight in some parts of the day.

Please help!!