If you enjoy it, it’s absolutely fine.
It annoys me a bit when people complain about other people spending loads of time on their phones. They don’t know what they’re using them for or what they’re getting out of it. I use my phone to read loads of news and current affairs, talk to family and friends all over the country on Facebook, have a laugh with other friends on Twitter, read books on the Kindle app, read book reviews on Goodreads, get support with my current fitness efforts, look at loads of nature, architecture, art, fashion and beauty accounts on Instagram, play games ... it’s all good.
With regards to social media specifically, I generally find social media to be good fun, and I don’t think I should feel guilty about a harmless and enjoyable activity. Different for people who find social media makes them anxious, of course. But if you like it and it helps you wind down, it’s totally fine.
I think there are apps that can monitor usage and tell you how much time you spent per day on different phone activities, so you could try using one if you want to know exactly how much time you’re spending.