You can take injection in morning and take the tablet at night. It won't be an issue..
Yes. You can start doing exercises for strengthening of muscles and joints.. Bones won't break by itself unless there is some pathology inside the bone..
Next Steps
You may have protein supplements, milk, curd, green vegetables, all types of pulses, fruits, etc...
Health Tips
Going out in sunlight for doing exercises / brisk walk in morning/evening will also help..