While short delays in periods (2-3 months) could be caused due to stress or minor issues; longer delays could be related hormonal/ endocrine issues, growths/ masses etc. Without a clinical evaluation it would be difficult to determine the cause of lack of periods or suggest a management plan. It is best advised to see a primary care physician or a gynaecologist for an accurate diagnosis and appropriate management.
Hope this is helpful.
I am 21 years old and have a similar situation. I havent had children yet but I havent had a period for 6 months .....I dont have insurance either but was seen for a very low cost by a gyn at planned parent hood clinic. I told them about my situation and they did blood tests to see if i had elevated prolactin levels (in reference to the endocrine problems suggested above) which were normal, and they also did a pap smear which was normal. They prescribed provera which is supposed to induce ovulation and bleeding which I will start tomorrow I delayed taking it because I wanted to give myself a chance to ovulate on my own naturallly...I didnt lol. The generic name for it is Medroxyprogesterone. It is used for this type of situation often I was told by the gyn. If it doesnt work for me I will request an ultra sound at planned parent hood clinic which they perform for $300.00, I want this test to show me if there are any cysts growths etc,as stated above.....