hi thank you for asking your concern madam and welcome to HCM. i would like make your doubt clear that you need not to worry for the missed pieriods if it is occuring first time since begining of your periods or since it is reguralised. this may happen due to any cause like pregnancy which will not be in your case, worry, stress due to any minor reasons. white discharge of very short duration and first episode can be neglected if it is associated with pain in lower abdomen, foul smell, itching, irregurar periods and painful urination then only we should think of antibiotics and consultation. keep your hygiene practice as it is. for the mouth ulcers drink plenty water, leafy vegetables as high fibre diet, b complex tablet also can be tried. it is not connected to your missed periods or white discharge. feel free to ask any queries thank you and regards dr. abhijit