I would second doing a more structured activity. I feel pretty comfortable in most social situations and I have a hard time going to bars alone. Maybe try one that has live music? That way you have an activity to occupy yourself with and an easy way to strike up a conversation with someone if that's what you're looking for. I really enjoy the Burren early on a weeknight. Sometimes I'll bring a book or my laptop and just hang out after work, before it gets too crowded.