See a specialist. A GP will not be helpful in this situation. I'll bet you're not even approaching menopause. Lots of women get preggers at 42, especially if they have had a child before. Ask for a referral, either from your GP or your ob-gyn, to a fertility specialist.
All tests we did was at our GP, blood and sperm count, and the results came from the hospital were the samples were done, so still not to go really, should my GP send us to a specialist?
You are certain you are starting menopause? 42 seems pretty young for that. Did a reproductive endocrinologist determine this, or your ob-gyn? Have your records sent to a fertility specialist (RE) right away and get some advice.