SIL Drama

New Mama
So my husband and SIL have a rollercoaster relationship which became even more passive aggressive when we got pregnant.  When we had the baby I ended up getting into a big fight w her despite trying to be mature at first.  So I was screaming (for the first time ever; over a decade, despite plenty of catty moves from her) w her 3 days postpartum.  Then I send her a long and thoughtful message in July trying to clear the air after she sent some upsetting texts to my husband.  No response to this day (unless you count her husband sending a few rude/unhelpful texts), but I get and invite to her baby shower next month.  She also sent a text to my husband (who still hasn't seen her since April) to say she hopes I can go.  My stomach sinks just thinking about it...I think I'm just going to send a gift bc she got us one!  Am I wrong here?!