It depends on how the relationship is going, if this relationship is a toxic situation it will definitely effect your health. Some of the symptoms are always stressed, extreme anxiety, mood changes and sleeping problems. To fix this, simply cut off the other person or if possible, try to fix things.
A) use your max heart rate, which is determined by subtracting age from 220
hope this helps :)
Trustworthy would be a government website.
Untrustworthy would be a media report
Hope this helps!
Seeing a therapist, a priest, taking soboxone (approved by a doctor. However can be highly addictive too), going to the doctor daily.