If you're feeling low on energy, maybe you should try eating more green vegetables, exercising and drinking loads of water. I don't think Berocca can do any harm but I would definitely stay off drinks with caffeine. Also you might want to try a pg supplement like Elevit which will help pick up your energy levels and is also good for your baby (it's known to reduce birth defects). I love my Berocca too…take it every day but during pg I also take Elevit for the extra vitamins for the baby.
Most of all though, take it easy, stress less! Take care!