How long does a strain calf take to heal before i can start running full speed its been about 7 weeks still hurts and feels a little weak ?

Need to see an DO: osteopathic physician, who specializes in sports medicine and/or cranial osteopathy. Because you sprained your calf, that means that there's also knee, hip, low back, neck, head involvement. It's not just the one area as PT treats. So be treated by an osteopathic physician, so you can start running sooner than later. Your body alignment needs to be balanced better, so you won't feel weak.