My own jealousy drives me crazy, while my girlfriend does nothing wrong. What to do?

Find out why you are so insecure. Has anybody you loved left you in the past? Don’t you love yourself, making it hard to accept the idea that your girlfriend loves you? Are there reasons to doubt her love? Are you uncertain about your looks? Talk bout these things with your girlfriend, getting insight in your own psyche. If you have the inclination to inquire after her where abouts, resist it. By focussing on your feelings instead of her behaviour it is clear to both of you that it’s your problem and not hers. This way you also give her the opportunity to reassure you. If you try to change her, you put pressure on the relationship, pushing her away. If you cannot solve this problem yourself, you should seek professional help.