Question about female hair loss at a young age.?

I am a 27 year old woman, I am in good health, although I do smoke,and I eat healthy but still indulge now and then. Over the last few months I have noticed that my hair has significantly thinned out. My ponytail is now half the size it used to be. I am trying to figure out what is causing it. I had a child 2.5 years ago but my hair bounced back from that just fine. I have had no major stresses or traumatic life events occur. My only thought is that maybe it is caused by ibuprofen because I have had a few minor strains and sprains lately and have been taking about 800-1000 mgs a day for multiple days over the last 2-3 months. Any information would be greatly appreciated. I can not visit a doctor as I do not currently have health insurance