What Are The Uses And Side Effects Of Stalopam Plus?

Three years ago I was prescribed Stalopam Plus for anxiety, the Doctor has prescribed the medicine for 30 days, but I continued the medication. For the last couple of months I have been trying to stop taking the medicine but I am finding it difficult as when I do not take the medicine I feel giddiness, lethargy & palpitation. I have also gained weight.
Please advice how I can get off this drug.