Yes, i think perhaps your mom is afraid that you will love your birth mom more once you do find her. She probably is thinking of mistakes she has made as your mom that makes her feel insecure.

Maybe you could try and use this waiting period to help her know you love her and nothing will change that. That you have enough love for her and your birth mom.

one of the hardest things to do is wait... wait for something this big and life-changing! Its nearly impossible to be patient... but I think the others are right.. it is just taking extra long and you should try again if you do't hear anything.

Wishing you the best!!