I pretended I didn't know someone today

I ran to the mall at lunch to go to GNC and get pomegranate pills since I'll willing to try anything natural to help, when I see walking towards me a woman from my prenatal yoga class.  The one I took when I was pg with my daughter. She is pushing a stroller with an infant carrier in it, so I gave a blank stare and kept going.  I just didn't have the energy to feign excitement for some random person I don't even know anymore. I'm pretty sure she recognized me which makes me feel bad, but only for a second since it's not like she was a friend.  A couple weeks ago I found out that another woman from the class is due in the spring with her 2nd and the other 2 girls I was friendly with already had their second babies. 

I'm not going to lie, it's getting a little hard right now.