As far as I'm aware, Panadol is totally safe to take. Too high a dose will place a lot of pressure on your liver, but if you stay within the correct doseage you should be fine.
Have you spoken to anyone about what's causing those headaches? Like Alisia said, they can be due to dehydration or tiredness. Perhaps tension as well? Sometimes tension headaches can feel like a band tightening around your forehead, sometimes around the back as well and can radiate down your neck and into your shoulders. You could try massaging your shoulders to see if that relieves some of the pain, but don't use too much pressure, particularly in the middle of your shoulder.
You may benefit from seeing a remedial massage therapist (who is trained in pregnancy massage) if you find it is caused by tension. Are you stressed at the moment? Are you aware of your posture when you're working, particularly at the computer?
It might be a good idea to get your blood pressure checked too... And generally just get looked after You deserve it! Take care and I hope you get some relief soon.