Hi. Motivation isn't easy especially for things that you just listed there.
It is something that happens to me as well so nothing to feel threatened about.
Good news is that it can be worked upon.
I came across this book "The Willpower Instinct: How Self-Control Works, Why It Matters, and What You Can Do to Get More of It Book by Kelly McGonigal"; it helped me to feel motivated and have the will power to go through what I decided I will do.
Next Steps
Self help books do help but only if you are not too dejected and can keep yourself on track.
I would suggest you to see a counselor for sometime so that she could keep you motivated to follow through it.My organization and I will be happy to help. Google 'The Mind Research Foundation' and you'll know what to do next.
Health Tips
If the books doesn't help (you can find her on YouTube as well under the same topic if you don't like reading) then I would strongly urge you to see a counselor/therapist.
Hope this helps.