At 31 weeks you don’t have long left at work so check your maternity entitlements. If your partner plans to take time off, look at his paternity leave options and organise friends and family to support you upon his return to work.
To help prevent pregnancy back pain make sure that you sit properly. The ideal posture is one where your neck is long, your chest is lifted and your pelvis is tilted so that your bottom is tucked under. If you sit for long periods of time at work, try to get up and stretch frequently. When sitting in a car, adjust the seat so that it is at a comfortable distance from the controls to suit you.