Im i pregnant or not?

its been 19 years since last had a baby yes along time but me and new partner long for a baby . i had my last period 30th jan 2011 and my cicle is 30 days i came off pill a year ago i worked it out i should have ovulation at 15 day me and partner always having most days .on the 18 day i had pink tiny bit of blood on tissue paper i not sure if that was related to a urine infection i have also had cramping whiched lasted about 2 days i have only had this affection since the bleeding day and one min it feels it gone then all of a sudden comes bk i was sick the other day for know reason after i had eaten. i feel exhausted and weak i had a few headaches and i noticed in the morning time the vein in my are much clear i am also got clear mucus from virgina when wiped i know my chances arent great as my age. thats why trying now before it to late.my oldest children are fine as long as im happy.please can you give me some advice .thanks