You should go a full week where you accurately measure, weigh your whole foods and count your calories... to be honest 300lbs is a lot, without even knowing your height btw...Whats your height?
Your maintenance calories (meaning what you really are eating daily is probably somewhere closer to 3000+. If you buy a weight scale and measure everything and count your calories, which is so easy now a days... download an app on your phone that accurately tracks calories (my fitness pal is a good one) and literally just count everything that you are eating even condiments.. If you were really eating 2200-2500 calories, you should be dropping weight with your current weight. unaccurately counting your macros/calories is one of the main mistakes people make and they start looking for other solutions.
I would not drop below 2500 with your current weight though. Just count correctly.
This advice is golden
U can have adverse effects of u get to low on ur cal
Like stated before ur not eating enough
Get a food scale some measuring cups and make sure that you weigh in portion everything out if you can't do that a good eyeball for 6 ounces of meat is about the size of your palm and The height of a deck of cards