Your message is so tone deaf.
OP’s feelings are so common / normal/ natural / understandable. It’s how SO many women going through infertility feel, and it takes very little imagination to understand why.
Infertility is one of the most devastating and painful things a person can experience.
Why shouldn’t OP be allowed to express and have her feelings acknowledged - In exactly the same way that OP’s colleague wants to express and have her joy acknowledged? People shouldn’t be forced to be silent about perfectly normal, human emotions , just because they are negative.
I hate this narrative that women experiencing infertility have to be quiet about their envy and grief, and instead have to pretend they are “happy” for others , when what they truly feel is a profound sense of unfairness, loneliness, pain and grief.
OP, you don’t have to be “happy” for your colleague, you can just focus on being sad for yourself. I agree with others, however , that the best thing is to just delete the emails or have them re-directed to junk. The fact is that most people don’t understand/ lack empathy for women going through infertility, and confronting the issue is more likely than not to cause bad feeling and awkwardness, which ultimately won’t be great for you. It’s less likely that through directly addressing the issue you will receive the understanding and acknowledgement you are seeking.
Sending love and best of luck ttc xx