I have done couch to 5k before. But now it's about 3 years since the last time, and I am much older, heavier and less fit. I did week 1 run 1 a few days ago and my hip hurt afterwards. Tonight I did it again and my legs felt heavy and I kept getting vomit in my mouth.... so I walked very briskly for the runs and just briskly for the walks. Is that ok?