I had 6 weeks off over Christmas due to tendon pain. I came back in Janurary but it was too soon. Ended up having a further 4 months of no running. I started jogging again recently. I'm having to build up slowly and anything longer than 4 miles is too much at the moment. Just did a 20:26 around the block and felt very strung out towards the end. I've lost a lot of fitness. How do I get back in shape on short runs only? I'm used to jogging for 1 hour or more at a time so I'm not used to this.