Running gets harder as the weather gets colder. Many people think this is a reason to stop running. Don't. Fall running is one of the greater experiences life has to offer. The leaves are golden, the sun so rare you feel blessed to bask in it for a few moments before it leaves for Africa. Don't stop running now, but make a few select improvements of seasonal running gear. A hat and gloves. Perhaps a wool layer. I run currently run in an icebreaker shirt I bought last year. I love it. I'm not buying anything new this year, with the exception of the new running shoes I got for my birthday. Quality lasts.
This week, try for 1500 meters. You can do it. We're getting closer to running a 3 k. Within 2 weeks, you'll be there.