Food???

So I'm going to be 10 weeks Wednesday and for the longest me and my husband have been wanting to go out to red lobster. That being said what i really want more than anything is a shrimp cocktail. Which is a glass with six shrimp and sauce in the middle. I know the shrimp has been cooked but not fully and is normally chilled on a bed of ice and i don't know if I am supposed to eat this since everything should be "fully" cooked or not contain Mercury which they do. So is it safe for me to consume this or do i just let go of this idea all together. Side note, i want crab legs same question really people say certain kind of crab is okay if anyone knows the difference please let me know, thank you all.