Weird vision changes..

(I'm 26 weeks btw)

So, I do suffer from migraines, but the spots I see when one is happening or coming is in my peripheral vision and looks like black birds flying around in the distance, so I don't think it is from an impending migraine. Today though...

I was watching my niece and she had something she wasnt supposed to so I bent down quickly and then lifted up quickly and put it in on top of the fridge. After that I was slightly lightheaded and then it looked like someone had dumped an entire bucket of glitter over my head. I saw flickering lights around my face for about 45 seconds and I thought it was really glitter from something and asked my niece if she saw it and she just looked at my like "wth are you talking about" then it went away.

Later I was using the toilet and when I stood up, no faster than usual, the glitter flicker happened again for about 10 seconds.

Can anyone explain why this is happening?