Fin Webbing Receding, Lethargic, Constipation

Housing
What size is your tank? 1.75 gallons
What temperature is your tank? 78 +/- 2 degrees
Does your tank have a filter? No
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? None

Food
What type of food do you feed your betta fish? Daphinas, Blood Worms, Mysis Worms, Pellets
How often do you feed your betta fish? Every other day. Treats once a week, Pellets 6 a day. 3 in Morning, 3 at night. Fasting once a week.

Maintenance
How often do you perform a water change? Every day
What percentage of the water do you change when you perform a water change? 50 percent everyday, weekend 100 percent
What type of additives do you add to the water when you perform a water change? Prime

Water Parameters:
Have you tested your water? If so, what are the following parameters?
Betta is currently with my girlfriend, water kit was purchased after he was moved.

Symptoms and Treatment
How has your betta fish's appearance changed? Fins appear ragged, Clamped, Stomach Bloats easily
How has your betta fish's behavior changed? Far less aggressive, lays on bottom of tank under leaf, possible flashing earlier when symptoms began, Bowel movement tool nearly a month
When did you start noticing the symptoms? Constipation was always as issue, fins and behaviour didnot worsen until 2 weeks ago.
Have you started treating your fish? If so, how? Heater purchased, Water Changes every day. Reduced feedings due to constipation.

Does your fish have any history of being ill? Constipation.
How old is your fish (approximately)? Purchased his first day of being stocked at petco. No idea.

I've always remained fairly consistent with betta care and water changes, however I fell victim to a stomach virus that lasted for over nearly 2 weeks and kept me mostly bed ridden and inactive. My betta Regal was active and constantly flaring and building bubble nests. Due to my condition at the time I was only able to change water once a week and this was before his tank was heated. Temperature never fell below 70 but his health seemed to slip as the "constipation" became more of an issue. I tried fasting and the pea treatment but bowel movements were still scare, worst taking almost three weeks to pass. As I said fin webbing has receded, however no discolouration is seen. His stomach swells after any type of feeding, nothing horrifying but I find swelling after half a pellet strange. No clolour loss, no signs of velvet or ich, although I did see flashing twice weeks ago. Not sure what else to do for Regal. Thanks in advance.