Does My Shih Poo Have A Cold?

Ok so i took my shih poo to the vet and she doesn't have any fleas.. she had 2 hot spots on the back of her head, which they shaved of and disinfected.. they gave me antibiotics to give her for the itching and de worming ( in case this caused the hot spots) they also gave me First Shield Trio Cream to prevent fleas... I took her to the vet on tuesday gave her all her medicines as directed by the vet everything was going normal... i decided to give her a bath yesterday (friday) she was ok with it i blow dried her and combed her hair, she slept for about and hour, we went to pet smart when she woke up she was happy got her a coat and a sweater ( it's starting to get cold out here) i out the sweater on her and took her for a long walk when we came inside she wouldn't play or listen to me or my husband she was just curled up in a ball and i noticed she had a runny nose.. she slept with us last night under the covers.... this morning my husband took her out for a long walk she was ok... but she doesn't seem to be too comfortable in her sweater ( does she think its a punishment?) could the flea prevention medicine make her depressed? or is she catching a cold? all she wants to do is sleep and cuddle am starting to get worried the vet is closed tomorrow i will take her monday but do u think its something serious???