She cannot catch it from you but the drastic change in weather certainly could have done it. As long as she is active, eating and drinking then you shouldn't have to worry. You can put her in the bathroom with a hot steamy shower and that may help her congestion and cough. If she quits eating, gets lethargic, gets a colored discharge from her eyes or nose she needs to see a vet as she most likely needs some antibiotics.
BTW- for some strange reason when I asked what she was the optional info. was not showing- I didn't want you to think I don't know what a chihuahua is!
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