I know how you feel about the heat. 3 weeks ago I decided to do a little spin around the neighborhood area, maybe 10 miles at most. It wasn't as hot as it had been (90 vs 105!), so I thought I would be ok. I probably got 3 miles into the ride and thought I was going to throw up and/or pass out. I limped home discouraged and defeated.
I skipped a few planned rides after that, and started making excuses to not ride. I was basically scared to get back on the bike again.
Finally, this past Sunday, I dragged myself out of bed early, and went down to the greenway, to do 12 miles. Well, 12 miles felt so great, I did the greenway 2x for 24 miles. I couldn't believe how happy and great I felt afterwards.
Sometimes you just need some time away from it. You don't have to be all in or all out. Sounds like there are times that you do enjoy it, so ride when the mood strikes you! Sorry about the stitches, but kudos to you for doing your own bike work. I hit the LBS for everything