Hi I was on 50 mg for 3 years and just recently my Docters increased it to 100mg took about 3 months before I noticed any difference.I would try and persevere on the dose you are on but if you are really feeling a lot worse go and see your docter.What I have noticed on this group that it appears that most Docters are on different opinions on the increase on dosage also time scales.Hopefully this is just a plip and you will start to feel better soon.
Good luck your doing fab so far x