What Causes Missed Periods, Bloating And Nausea?

hi im 46 sterilised 12yrs ago and have missed my period which is very unusual, i feel bloated, no sore breasts which to is unusual as they are at least 7 days before my period arrives..could i be pregnant..i feel tierd and unwell but cant put my finger on whats wrong..or maybe its the menopause? im working away from my home country so i cant get to my gp for another 5 weeks?