I started a new job in March. In the past I've been a shy person but I felt I'd definitely improved on this in my working life.
But in this new job I'm really struggling to fit in. I try and make conversations with colleagues and talk to them over lunch, but I'm getting a really strange vibe. The answers I get are always short and one worded, and it's obvious they don't want me there. When I'm there they fall silent and I see them exchange looks with each other before going on their phones (to message each other?) They all have their own 'groups' they sit with at lunch etc, and it's clear I'm not welcome and don't fit in with any of them 
But the problem is, the managers have started to notice this and think there's a problem with me. They have spoken to me to voice concerns about me not mixing, and are behaving as if I have an issue. I've said everything is fine, but I'm growing concerned. I'm obviously on probation and me not fitting in with the team could be an excuse to get rid of me. I always speak to colleagues and go to out of hours events, but it's not working 
I guess I'd just like some advice. I've had a shit few months and losing the job would be awful for me right now 