Big breasts are ruining my life.

I’m 18. A year ago I was a 34D but since then I’ve gained weight and I’m a 36DDD!! I am finding it frustrating and difficult to find a bra that will fit properly. All of the cups on my bra LITERALLY FOLD under the weight of my breasts. Every single time I bend over to grab something off the floor for example, my breasts fall out causing the stiffness of the cups to ware out and then overtime (like 2 or 3 uses, literally!) those bras basically garbage. It’s embarrassing to have to hold them in at work every time I bend over, or having to keep checking that they’re still in my bra. And on top of that every time I put my breasts back in the cup it’s uncomfortable when my nipples rub against the bra. I also cannot workout if it involves jumping/running which makes it hard to lose the weight I gained. I tried on a sports bra at the store and literally broke the front zipper, I feel awful about this all. Can someone PLEASE help!! And preferably not a bra that costs more than $50? That’s a ridiculous price that I can’t afford to spend on one bra.