Hello,  
Thanks for the query to H.C.M. Forum. 
Since you took 
diflucan ( 
fluconazole 100 mg ) for 12 days for yeast infection after properly diagnosed. 
It was mere coincidence that there was hairs loss . 
Diflucan never causes hairs loss as I am prescribing this drug from last many years without any complication . 
Mild degree 
nausea, 
vomiting m 
dizziness take place with this drug . 
Reason of hairs loss may else one as, 
1 
Dermatitis scalp , diagnosis can be confirmed after physical examination by a Dermatologist. 
2 However one of the most important reason of hairs loss may be 
fungal infection over scalp ( along with 
esophagus , however as you described in your query that  there was fungus infection in esophagus so this fungus infection may be the cause of hairs loss as well ). Fungus in scalp causes 
dandruff , so hairs loss.Diagnosis can be confirmed bu a dermatologist . 
3 Deficiency of 
biotin, zinc ,
calcium pantothenate may be responsible for hairs loss. 
So in my opinion 
consult a dermatologist and get his opinion regarding this problem . 
Tension is one of the most important cause of hair loss. 
Good luck. Dr. HET