Go to your ob gyn. Get a low dose estrogen patch that you will put on when you feel PMS symptoms. I use a patch called Vivelle for maybe 3 days a month. Solved my problems and I had ZERO side effects from the patch.
I've never heard about taking anti depressants for a week at a time for PMS but obviously women are having success which is great. The more options, the better!
Personally, I would try the estrogen patch first. I was a pharmaceutical rep for 12 years and sold antidepressants....they are great but rarely without side effects which typically are transient if you take them every day continuously, and then they usually disappear after time. May be a different ball game if you take them for a week and then stop for 3 weeks.
You may have the side effects for the entire week each time you restart them up.
Your estrogen levels drop prior to your period and thats why symptoms flare at that time. A low dose patch will give you higher hormone levels and "even you out" if you will.
I use mine along with my IUD so I think it's safe to use with other birth control but your doc will know.
I used this to help with PMS migraines and it worked!!