Stopped Contraceptive Pill. Have Nausea, Stomach Cramp, Headache, Lower Back Pain. Worried

Hi, I have been off the contraceptive pill since the start of October 2012 and myself and my partner trying for a baby ever since. I have just turned 35 years old. My cycle appears to be around 35 days. On day 29 last week, we had sex. For about 5 days leading up to this, I had the usual mild stomach cramps I normally get with expecting my period. During sex, i had mild spotting or mild bleeding. It did not continue afterwards. We then had sex again 2 days later, and the same thing happened. The bleeding didn t really continue. The the following day (yesterday), I started bleeding (day 32 of cycle) and had the most awful nausea , stomach cramping and aches around the lower back and pelvic area. I also had a headache and was very emotional. The nausea has continued, sporadically - I feel sick at the thought or smell of certain foods. Especially savoury food, and don t have much of an appetite . Today, I still feel slightly nauseas and don t really want to eat anything and still have mild bleeding. I have never experienced anything like this around or just before my period is due and am worried it could be something. Many thanks, Becky.