Aaawww! You are just sick with some bug and you should ask your parents to take you to see the doctor and be treated. The thing about your period is normal. Some women don't become 'regular' until their early 20's. Don't worry about your period, just be ready for when it arrives, and only worry if you have odd symptoms with your period. Blessings - Blu
As you have been ill now for two weeks and still have congestion in your head and still coughing, it would be a good idea for your parents to take you to the doctor. The headaches may be from congestion or from your temperature being higher than normal. The doctor can examine your chest, ears and throat to see if you have a bacterial infection. This would be treated by a course of antibiotics.
If it is a viral infection, then no antibiotic will help that.
Keep warm and drink plenty of warm drinks like Ribena, honey and lemon and anything that you like, but because you have a tummy problem and have vomited, avoid all milk products until you are well again.
At home your mum can make you a steam inhalation. A bowl of hot water with vick or Olbas oil. Cover your head with a towel and lean over the bowl of water and breathe in the steam. Take care so as not to get scalded. You can also apply Vick to your chest, neck and back. This will help to decongest you and loosen up the mucus.
Your mum can give you pain relief that is suitable for people of your age.
As regards your periods, when you go to the doctor with your mum. Get you mum to ask the doctor if he can do a blood test to check your levels of iron. If you are not eating properly you can become anaemic. This means that there is not enough red blood corpuscles. They carry oxygen around our body. If you are anaemic that will cause lack of periods and tiredness.
Your mum could also put you on some multivitamins that are suitable for people of your age too.
Let us know how you got on at the doctors.