The teen star was rushed in after becoming sick following an appearance on Jay Leno's late night talk show.
And Gomez, 18, says her junk food diet was to blame for the crash.
'I am doing much better, I am good, I just need to take better care of myself,' she said on Good Morning America.
'I was very low on iron, I was dehydrated and I was just exhausted.
'I am 18 so of course I want to eat whatever I want. My mum has definitely been stocking up on the vitamins.'
Gomez, who is dating teen heartthrob Justin Bieber, says she is not sure if the couple will ever record any songs together.
'I am not sure, whenever I do songs I do them organically so if it happens it happens,' she said.
'I am young I spent the first three years hiding and terrified about things like this so I am enjoying being young and having fun.
'I can't shut it all out, I am human, I read what is going on but I try to shut it out.'