Cold, throat pain, fever, irregular

Since 4 5 days I am suffering from throat pain and i am unable to swallow anything without pain even it pains while sleeping when i swallow spit. There is a swelling also on the lower left cheek, my dentist friend suspects some infection. Since two days I am getting fever in night, morning it reduces. Since January month my periods have got irregular. They are coming twice in a month.  On 16th December I took medicine for vaginal pain and UTI after consulting a doctor, before that I used to get regular periods but after that in January I have started getting irregular. Following are the dates of period- December-10th-15th regular (on 14th no period) January-14th-17th regular 25th-29th spotting (28th no spotting) February- 2nd-6th again period From 23rd again period Why it's happening?