First off, there is rarely such thing as 'too much protein' for an exclusively carnivorous (or more accurately insectivorous) animal. You may hear rumors flying around that live/frozen food is 'too rich' to be fed on a regular basis, but this is a load of BS. While it is true that you need to feed a wide variety of frozen/live to form a complete diet 'richness' has nothing to do with it. Think of frozen or live foods as spinach or steak. Healthy? Yes. Could you survive off steak or spinach alone? No.
Therefore the best way to go (unless you want to have 25 live foods on the go) is to base the diet around 2 or 3 good betta pellets such as Hikari Betta Bio-Gold, Atison's Betta Pro, Kent's Betta crumble or HBH Betta Bites, then supplement that with feedings of live/frozen food several times per week.
Since live or frozen bloodworms are easily digestible I am assuming you are using freeze-dried. This type of food is very harsh on the digestive system and should only be fed if pre-soaked and even then only as a treat. Considering how much they swell inside the betta's stomach its no small wonder that they cause bloat. A betta's stomach is about the size of his eye so even a few freeze-dried bloodworms can cause a lot of trouble when they swell up with water ot 3x their size in the gut.
To treat, fast him for a few days and then if you are in a pinch, feed him a thawed, deshelled frozen pea. A more natural alternative is to feed him daphnia, aka the water flea, a small freshwater invertebrate that acts liek a laxative.