antibiotics or no?

SD

my baby girl is 14 months. She has had a fever since Fri night that won't stay down. No other symptoms but she just cries and I can see she is not feeling well. last night I took her to the ER because my mom basically screamed at me and made me feel bad. We sat there for 3 hours waiting for her to wee in a wee bag in her nappy so they could test her urine. Eventually they used an in/out catheter to get a sample and it turned out to be clear. The Dr said she doesn't know, and said she looks well and the temp is down. Then my daughter literally coughed once and the Dr said "Oh she coughed, it could be her chest" and listened to her chest AGAIN even though 2 hours earlier she had listened and said it was fine. Ears and tonsils were also fine. So she basically said she can't send me home without a script for antibiotics but it must be something wrong the antibiotics will fix it.

Would u just give her antibiotics without knowing what's actually wrong? She's been on antibiotics twice this year already. Or should I phone her paed? Or wait it out and see?