How do I not feel lonely on my own

I hate being alone. I feel like the loneliness is eating me up and I don’t want to fall down that hole again. I didn’t see my bf for 10 months due to COVID so I have just stayed round his for a month and a half and it’s been the happiest I’ve ever felt in a year. Now I’m back at my house I feel so lonely without him.

How can I stop the loneliness