muscles in legs and foot not working after sitting down

I’m 26.5 weeks and I just stood up from

sitting at my office desk for a while.. and it was like my whole left leg was jelly!! Terrifying, and I fell over but luckily caught myself on my dogs bed next to me so I didn’t get injured. It was almost as if my leg and foot was asleep but it didn’t have the normal tingling sensation. This must be that chemical relaxin I have been reading about that our bodies release closer to delivery. Be careful mommies, we are so susceptible to falls!! I am shocked this happened as I am very careful to exercise all the time.