AITA for getting mad at my girlfriend because she complained about not spending Valentine's Day together four days after my father passed away?

My father passed away last Monday after being sick for almost two years. This has been an extremely difficult week for me and my family. Today is Valentine’s Day, and my girlfriend texted me asking if I wanted to watch or do something together tonight. I told her I was going to church because we had an activity planned, and I had also offered to drive some of the younger members, so I wouldn’t be able to come back early.

She said she wished I had told her sooner, but then she added that she feels like she’s always in second or third place and that I should have explained things to her in more detail. At that moment, I got really upset. I lost my dad just four days ago—I haven’t been in the right headspace to think about celebrations or make plans. It felt like a complete lack of empathy that instead of supporting me, she was making me feel guilty for not prioritizing Valentine's Day while I’m grieving.

I felt like responding sarcastically with something like: "When I die, I'll make sure to ask my dad why he chose to leave right before Valentine's Day and ruin an important date in my relationship," but I held back because I knew that would just escalate things.

On top of everything, I’m also dealing with a legal battle. My father had a previous relationship before my mom, and he had kids with his ex. While he was alive, he helped them financially because he felt bad that they couldn’t get ahead without him. Now that he’s gone, his ex and my half-siblings feel entitled to take control of his business and are demanding money from us—even though my dad left everything to my mom, my brother, and me in his will. His ex is even claiming that he owed her about $1,000 and insists we have to pay her.

Even though the law is on our side, that doesn’t stop them from causing trouble. My half-siblings used to work for my father, but they were fired for stealing, so we’re honestly afraid they might try to harm us or the business. My mom and I are trying to make fair decisions to avoid conflict, but it’s incredibly stressful.

With everything going on, I have zero mental energy to deal with my girlfriend complaining about Valentine’s Day. So, AITA for getting mad at my girlfriend over this?