Toddler fever

Okay so I need help for 2 weeks my 3 year old daughter has been sick with a cold but the first week she had a fever for two days and then and went away then this week she got it again and now she's had it for 3 days it goes up to 101.1 , we took her to the ER and they said everything was fine and that it was just a virus like a cold so we got sent back home but I'm getting a little worried and I don't know if I should take her back to the ER again or make her an appointment or what she's never had it like this before where her fever goes away and then comes back it's never happened before and this whole time I've been waiting for my 2 other kids to to get it and they haven't gotten it the only thing they have is a runny nose which is when me and my boyfriend have as well but nobody has had a fever but her. She's been eating very little not too much and when I give her tylenol it goes down to like 99 but then it goes back up and once it goes back up she's like really irritated and fussy and just cries so what should i do?