05/10/2012 at 06:00 AM EDT
isn't letting a reported split
from longtime beau Nick Loeb totally get her down.
The Modern Family
star was in good spirits on Wednesday at the Einstein College of Medicine's Annual Spirit of Achievement Awards at the Plaza Hotel in New York City.
"She [seemed] in the best mood," an onlooker tells PEOPLE of the actress, who was invited as jewelry designer Lorraine Schwartz's guest. "Mother's Day is this weekend, and she talked about her son and how proud she is of him and how he's such a nice kid. No matter who came up to her table, she was taking pictures and people were being introduced to her."
Vergara also apparently had quite the appetite at the daytime affair.
"She was scarfing down Twinkies and popping them in her mouth," the source says. "If there was something fazing her, you couldn't tell at all. She just didn't care. She did every media interview and was chatting with people. You couldn't tell anything was wrong." – Melody Chiu