SD Ticked Off - Again. Is it the Prozac?

We can't figure out what is wrong with my sd.  She's so angry all the time anymore. The only time I hear from her is when she thinks she has to complain about something.  I asked hubby if he talked to her last night and he said they argued last night, like usual (usual since Prozac, not usual over the last 18 years).  Is it possible that Prozac has changed her from the sweet kid she was into the hostile person she is now?

We can do nothing right apparently.  She graduates in June.  She planned her graduation party in July. We can not afford two trips to their state within that short amount of time.  We are going to her graduation ceremony because that is most important.  A party in July - not so much.  A party with her mother's side of the family who hates us - definitely not so much.  We had asked her months ago if we could take her out after her ceremony to celebrate and she said no.  So yesterday, she asked me on facebook why we weren't coming to her graduation party too the next month.  I explained it to her (finances, it's not that we don't want to but financially, we can't swing two out-of-state trips so soon).

"Well, if it's such a hassle don't bother coming at all then."  (That's what she told me.)

I realize you have been warped by your mother and are now spoiled, never having to work for anything and have no concept of financial responsibilities but grow the hell up.

No, I didn't say that to her.

I told her we loved them and missed them and wanted to see them and were coming to see her graduate in June.  All I got back from that was a "yea" - yea, what?  Yea as in "ok, sorry I bitched at you because you didn't deserve it? or "yea, right, I don't believe you"?

After that, I guess she moved onto her dad to complain to him all night long while he was at work.

I'm so tired of this.  

Does anybody have any personal experience with Prozac?  Can it make a normally nice kid hostile and aggressive?