Is this a good enough excuse for not going to a friends baby shower?

Ive been TTC since February, I got pregnant the first try but had a blighted ovem miscarriage. It was devistating and I was an emotional wreck until after the D and C. I've had one period since then and it took 6 weeks to get it! So of course I thought I was pregnant b/c I was late AND had positive pregnancy tests (they were positive still from the miscarriage as I found out later). Got my period and NOW I'm 36 days into this cycle, I'm late! So that means I'm pregnant right? Wrong! Tests come back negative!!! I think I'm finally going to get it soon because I've been a wreck the past two days. My emotions are raw, understandable I hope. So my question is, my friend is having a baby shower today. I RSVPed that I'm going but that was a few weeks ago. Now I don't know if the party is going to be at trigger or wha and I'm really worried about having a meltdown in front of all of the guests. Help! What should I do. I really don't want to go but I don't want to be rude or selfish. Any suggestions?