Am I pregnant? I feel like I have the symptoms,nausea,bloating,and sleepy all the time.?

I am 18 I don't want criticism I want advice. I am not sure if its stress, or if I am pregnant. I have done some research online. I was on antibiotics about a month ago, from having a tooth pulled. And my boyfriend and I have been together 3years,I have yet to say anything to him. I graduate in May so its not like I am extremely young I have bee experiencing random nausea all through out the day. I get dull headaches, My back hurts but not unbearably. If I smell certain foods I become nauseous (bacon, eggs, cinnamon, cheeses) I have had an urge to drink lots and lots of water lately I am not sure if that has anything to do with it. I would keep the baby my boyfriend is 19 and we are in the process of looking for a place to live,we live with my mother and step dad now. Just tell me what you think.Please don't be rude.