What's happening to my boobs 😩😩

So I have quite large breasts, I wear a DD with extra padding to give them a nice lift with cleavage. I could wear an E but I feel they don't look as nice in clothing with an E because they're naturally very separated my boobs and come down low. My boobs are one of my favourite body parts and I always get compliments on them. In the last few weeks I sometimes before bed massage them with olive oil as I read once it's good to tighten them. Now in the last few days I've been looking at them and they've gotten soo many stretch marks at the top and they've gone sooo soft and squishy but it's not nice at all. Especially my left breast (the larger one) I can literally flap it around where as it used to be so nice and firm. It's really depressing me now any help on how I can firm them up again ? Do you think the olive oil made them like this or what could it be ? Even my thighs have gone like this so squishy. Any help would seriously be much appreciated ! Xx