Parents going abroad 2 weeks before due date

My mum told me today that they are going abroad two weeks before my due date. I came early with my son (by 3 weeks) who is now 15 months. They are retired and could go away anytime, but have chosen the first week of September. If I have just had my second baby, who do I need more than ur mum around to offer support? And of I've not, I'm gonna be massive, have a toddler to contend with and would have really appreciated them being around in case I went into labour whilst my husband at work etc. I feel really let down by them. This isn't the first time they have done stuff like this. Am I being unreasonable? Any thoughts would be appreciated. Thanks