"I don't know. The past has a funny way of sticking with us."

She knows what he means, he's sure. And he can vouch for what he's saying as well. Shifting a little, he continues,

"You've been through a lot, Heather. You'll probably feel that way for a while."

Initially, it might not even be up to her. What is up to her, though, is how she decides to deal with it, and he thinks she can do that just fine.