Have you tried talking to your gynae about fertility screening? If not you can try to consult them about it. You may also want to try my gynae Dr Regina Ng if you're near Clementi. We went to her previously for pre-conception planning and she really helped us in conceiving naturally (though some...
Do you have relatives (parents/siblings/etc) who can help? That's what we need when our 2 children (only a year apart) did when both me and my husband were both working full-time. My hubby's parents stayed with us temporarily to help care for the children.