I feel uncomfortably full after eating small amounts

I am a 41 yr old woman who has experienced a weight gain of 15 lbs in the last two years despite eating well and exercising. I now weigh 150 lbs and seem to hold my weight in my stomach.  I do experience heart burn and reflux occasionally and use over the counter ranitadine which works.
I also experience bloating or feeling extremely full - like I cannot digest my food properly. I am not constipated and I seem to lack energy these days - feeling lethargic.
I ate a very small bowl of cereal this morning with some fresh raspberries on top and here I am almost 2 hrs later so uncomfortably full I am unable to exercise.  This cannot be right - I have an appointment to see my doc next week, any input would be beneficial, thanks!

[patient915]

Welcome to the gastroenterology community!  I would recommend seeing a gastroenterologist about this.  You might need a gastric emptying scan to check for gastroparesis (slow emptying of the stomach).