Try to rest/sleep when your toddler is also doing so. Your body is doing hard work growing a baby inside so that is very important that you need to rest too. Your baby can get affected when mum is not having enough rest. I've been a sahm when my kids are small and still is and also currently pregnant. Not everyone can afford to get a helper so I do everything by myself. Now that my kids are grown up, I divide the house chores with them & my husband. It's ok if your house is a mess since you have a 2 yr old. It's ok if you just cook a simple meal as long as everyone in your household is full. They need to understand and know that you're heavily pregnant now. Share your workload with your husband. Ask him to look after your son while you take a quick nap to recharge. Having children is a big job and lifelong commitment so both partners needs to play a part and understand each other's exhaustion.
Hi Mum, I would suggest to get helper so that you can spend more time with your son as well as take proper rest. Also, do divide housework with your husband :)