SIL didn't take my pregnancy so well

I just need to rant real quick. I'll never understand how women are so bitter towards other women for being pregnant. My husband and I have been TTC for 4 years now. We never mentioned anything to anyone about TTC besides my mom. I had a miscarriage that my in laws now know but my husband and I are very private (we don't like outside opinions) anyways we announced our pregnancy to his family after the dr told us we are healthy and growing. Well his SIL who is also TTC legit threw a temper tantrum and starting yelling, cussing and crying at us. Told us how inconsiderate we are for getting pregnant before her. I'll never understand how some women can't be happy for others. I understand ttc can be stressful and painful but I never got bitter or nasty to anyone I knew that got pregnant. Rant over