Need some advice

I have been big person all my life. Few years back I dropped like 60 pounds in 4 months with extreme diet and also doing a physical activity all day and playing volleyball 3 to 4 hrs a day. Its been like 5 years and slowly I gained all of the weight back and even more until last year I was able to drop the weight like 10 to 20 pounds easily now I crossed the 300 pounds and I feel like I am unable to drop the weight. Please give me any suggestions that’s could help me.