Switching from Luvox to Prozac (fluoxetine)

I have been on Luvox (Fluvoxamine) for about 3 or 4 years now for panic attacks/anxiety disorder. Lately, it has seemed like it has stopped working and losing its effect.


The past few weeks, I have been feeling "out of it" all day. I have Googled my symptoms and all point to depersonalization & derealization.
This feeling is very similar to the "withdrawal" symptoms I get when I miss a dose or 2 of my Luvox.

I also have had trouble focusing/concentrating the past month or two.

Went to psychiatrist; was put on Vyvanse for ADD.

First of all, is it possible for the Luvox to "lose its effect" after this long? And could it be causing these feelings?

I went to the psychiatrist today. He gave me a prescription for Fluoxetine (Prozac?) 10mg and told me to take this tomorrow instead of the luvox, and to just stop taking the Luvox. I have always thought that you had to wean-off of Luvox... because of the withdrawal symptoms.
Or, since the fluoxetine is an SSRI, and Luvox is an SSRI, they will "work together" so I don't get these symptoms.

Has anyone here had this feeling of depersonalization? How did you cure it? What was the root cause of it?

And is it okay to switch from Luvox to Fluoxetine like this?

Thank you, I appreciate your help!

I remember taking prozac a few years ago and it worked really well for me. Perhaps you don't have to be weaned off the other tablet, some you can just stop.