Celosia indoor

[oguru25]

HELLO!!!
I just got a beautiful pot of celosia plant in October, with vibrant green leaves and blooming flowers.
Once I received into my house after a few days the leaves started wilting, flowers drooping.
Searched online and said it needs plenty sunlight, so I took it outside for sun exposure a couple days.
I live in southern part of US, and the wind is picking up recently, so the plant has been staying inside. The wilting leaves started having dark spots and holes, and the flowers are becoming more droopy.... I'm sure I'm not giving it the appropriate care, but can anybody advise what I should do in this situation??
I don't know if it's got fungus infection? What are the little black dots?

Attaching 3 pictures of its current state, I'm so sad to see it become like this only after a couple weeks of my care.... T_T

 

[Marck]

Plume Celosia (Celosia argentea), in the Amaranth family (Amaranthaceae), is a tender annual. It is dying as the weather cools in late Fall.

If you want to try to extend the plant's life, you could grow it indoors, on a sunny windowsill. This might restore the plant for awhile longer, though eventually the plant will expire. Next Spring, it would be easy to grow more from seed or starter packs, if you so choose.

 

[oguru25]

Thank you Marck! So it's just a normal cycle of life?
Are the black dots its seeds?

 

[Marck]

The black dots I see look more like caterpillar frass.
However, you might be able to collect seeds from your plants.
Look near the base of each plume-like inflorescence where there may be fertile fruit capsules.
If present, these will easily rupture when ripe, releasing small black seeds.