Dizzy spells/lightheadedness at 35 weeks?

Throughout my pregnancy I have not once felt dizzy at all, in my second trimester I did feel quite lightheaded when I stood up too quickly, but it only lasted for around 5 seconds, and obviously I knew I was feeling like that because of standing too quickly.

Randomly today I was stood talking to a friend and I felt extremely dizzy, my ears started burning and my vision went blurry, so I had to sit down. I felt like this for a few moments but I was completely fine afterwards. Has anyone else felt like this? I’ve never in my life felt dizzy, and I haven’t felt dizzy throughout my pregnancy either so it’s all new to me! Hopefully I don’t feel it again because it was so random and onset.