Check your vitamin D status urgently, and consider recommencing breastfeeding (if stopped). Low vitamin D is closely correlated with depression. If it is low, you will need the usual megadose to quickly get levels up. It is also important to get regular exercise, preferably outdoors, as this helps enormously with depression and will also help you get adequate vitamin D. It might be worth considering counselling.
Recent research confirms that breastfeeding is protective for the mother against further MS attacks while she is breastfeeding. Once you take a megadose, it will help your baby/ies get their vitamin D levels up (through the breast milk). That will reduce the risk of the children getting MS, and once they stop breastfeeding, vitamin D supplements should start as per the instructions found on this website.