I am 15 years old, and am really worried. My boyfriend and I have had sex about 5 or so times, both our first partners and havent done so in a few months. For the past few days Ive been having sharp abdominal and stomach, nausea, a cough and general fatigue, and also diarrhoea and constipation alternating. Then this morning I found two ulcers or sores, one on my labia and one on the opening to the vagina. They're about half a centimetre wide, are itchy and sore, and are a dark red almost black in colour. they bleed a little bit but theres also puss, and they have a strong outline and are slightly raised. I am not sure whether it is more likely to be a symtom from my stomach bug or an std? Or if It sounds like I should go to the doctors asap? if anyone can help i would really appreciate it.