It can come from sulphur. And it can be a calcium sympt. Would not advice to take anything without clarifying the last remedys you have taken. If sulph and its a old reocurring symptome, it should leave after 48 houers max, or the potence is too low, if never had before, its new, and points to another remedy, as calcium, who is likely during preg.And then antidoting of sulph is nesseceary.