You sound a lot like me. I started on the 0 to 5km program a couple of years ago tonget fit and lose weight. Didn't really enjoy to start but kept with it (something to do with reaching 40 and thinking I really had to do something).
Two years on I'm no super athlete, but I really look forward to going out now and enjoy my runs.
Summer is a tough time for me though. I'm happy to run in snow, ice and rain but as soon as it gets above 20c outside I know I'm going to suffer. I have to run less, run slower, and drink loads when I get back. I know what it feels like to keep sweating half an hour after the nice cool shower.
All I can say really is, enjoy the autumn. Must be my favourite time of year to run now (although winter and spring are ok too). I'm not going to be a great runner so I don't really worry too much about slowing down a bit in the warmer weather.
Keep going, with any luck you will push on through the 'doing it because I have to' phase and actually start enjoying it. I did, and lost 10 kg in the process. Good luck.