Help plz 35 weeks 2 days

I am 35 weeks pregnant my question is for last week every time I walk it hurts I have like sharp pain I went to the doctor and found out that he is head down and he is pushing on my pelvic so that not what I am worried about but it started last night I felt like I was having contractions they would come and go some hurt more then other well today it started again but this time I am hurting to walk I am nauseous I am just very uncomfortable!!!! How do I know if there real contraction or not!!!! This is my third baby but my other two were c section I never had any of this so I don't know how to tell I am schedule for a c section in 3 weeks!!!!! Any advice I would appreciate it thanks