I 17M am obsessed with being in a relationship

To give context for the past 2 years I have constantly been in different relationships/ talking stages with around 5 different girls without letting myself build and just rebounding again and again.

I broke up with my ex girlfriend about 3 months ago now and I still feel attached to the thought of getting into a relationship and the dependence on other people to pass the time rather than myself.

I’m not the most social of people so I have a lot of time to myself and end up going on instagram and Snapchat and talking to different people all the time.

I started the gym at a similar time to the breakup and I thought that would take over as an obsession but I just can’t get the thought of a relationship out of my mind.

Please can I have some advice on where to start rebuilding my outlook on life away from just relationships.