PLEASE HELP! My small betta died suddenly today. SBD?

I have owned male Betta fish before that have lived quite long lives but this was my first female and the first to develop illness. I have had a very small female Betta fish for about two weeks and she has seemed very healthy and active until this morning.

When I saw her this morning, she looked like she was dead, floating near the heater at the surface of the tank. I tapped the tank and she moved her front fins a little and produced a lot of bubbles at the surface from her mouth (almost like vomiting???). After examining her a little closer, I saw that the front of her abdomen was very swollen.

I read up online and figured I had just overfed her and should wait for her to pass the food. For about four hours she didn't move much expect for her gills and floated around the bowl at the top of the water, continuing to make those little vomiting bubble motions. I didn't see her defecate at all during this time.

After doing paperwork at the desk where my betta sits and monitoring her for about five hours, I left for lunch. An hour later, I returned to find her dead at the bottom of the bowl. ):

I keep this betta in a 1.75gal bowl with an ambient heater that should keep the water around 75-77 degrees all day. I do not monitor water temperature with a thermostat but the heater is always working and her water felt warm all day.

I fed my Betta freeze-dried blood worms, but since she was so small and I was worried they would expand in her stomach, I would cut them at least in half and soak for a few minutes in a small cup of her tank water. Once the worms were tender and expanded, I would feed the Betta, no more than two or three worms a day. This little female has been very hungry and eats the worms immediately. Did I overfeed her?

I'm just so surprised this came on so suddenly. She has been so hearty since I first got her and I didn't feed her any more than usual the night before she became sick. I didn't feed her anything at all today before she died because she appeared so bloated. What did I do wrong? Bloating or swim bladder problems?

Please help! I want to make sure this never happens again.