It is definitely a difficult time to be waiting for medication to kick in. Your doctor probably started you on 10mgs to see how you do after it begins to work. It can take up to 14 days for you to start to notice a difference. Sometimes, SSRI's can create an uptick in the anxiety you're feeling.
If you can wait it out around 4-5 more days, that would be great! If not, you may inquire as to whether you should increase your dose.
Are you also seeing a therapist? If not, would you consider it as supplementary therapy? It is often helpful, especially when starting a new medication.
I am sorry you're going through this and as you can see from the many endless posts on this board, you're not alone! I've had similar fears of "depersonalization" and they can be very frightening. If at all possible to distract yourself with something you really like to do- I'd highly recommend it!