Feel lonely as hell on my birthday

Just need to vent. Tomorrow is my 30th birthday and I’m feeling lonely as hell and pretty much invisible. I am pretty close with my 2 cousins that are sisters, they decided to take a weekend trip on my birthday with their families to a cabin in Lake arrowhead. I also found out that another couple that my husband and I are close with also we’re invited and they are going... but I never got an invite. Not even on my birthday. I’ve been pretty busy with my baby lately and haven’t had much time to keep up relationships... but I just feel hurt that I wasn’t even invited. I seriously feel like I have no one. Motherhood is so lonely.