You sure were'nt eating very much before!
OK, here are the facts:
How many times a day are you eating this? If a "few" means 3, you've added about 600 calories to your daily intake. 1400 calories total isn't a lot, but you've gotten your body used to 800. I think you need to back off a little of the extra calories and introduce them more gradually.
Explanation #2: Are you using any non-scale measures of your progress? You may not be in a stall at all! You may be building muscle and dropping body fat at an equivalent rate. Quite possible for the first few months of a weight training program. When I first started lifting heavy, I weighed 135 pounds with a body fat reading of 27%. After three months (and I was eating
more), I still weighed 135, but my body fat % was 21, and my pants size had gone down by two sizes. Definite progress, but the scale said I was in a stall. I'll take that kind of stall any day
Mel