Can toddler sense early pregnancy?

Ok this might be a strange post but I’m just curious... my boyfriends 2.5 year old son is normally my best friend and loves me (me and his dad have been together since he was 10 months old we have him staying with us 2 nights a week). His little boy and I have always got on well and he is very comfortable with me, gives me cuddles and calls for me a lot. The last weekend we have had him he has completely changed with me. I couldn’t say or do anything right it was completely out of the blue and out of character. I was and am heartbroken as I don’t understand what has happened 😭 I’m hoping it’s just a random phase and that next time he is with us our relationship is back to how it normally is. But it got me thinking... me and his dad have been ttc for 8 months now with no luck as of yet. AF is due to arrive tomorrow but I took a test today and I’m convinced that I saw a very faint line. If it turns out that I am pregnant do you think that my boyfriends sons change of behaviour towards me may be down to the fact that he can sense that I’m pregnant ? What are your thoughts ? X