My son is very attached to my helper even though she only joined us 2 months ago. So much so that when he wakes up in the morning, he wants her and cries if I try to hold him instead. It's quite distressing - why is he doing that and what can I do?

If your helper is the primary caregiver to your baby, then I think it's perfectly normal for him to want her or look for her since she is her source of comfort and security most of the times. As a mother, I understand that it might hurt if your baby prefers her over you especially when you look forward to spend a litte time with your baby during the off days. Perhaps you could spend more time with your baby once you are back home? It could be a little tiring and stressful but I think it would help if your baby gets to interact with you a little before he sleeps and ends his day. Also, if he night feeds, attend to him instead of the helper and jump at any chance that you use to bond with him. Hopefully this way, it will help you to feel a lot more closer to your baby.