Feel like I'm being treated differently

[lou732]

So I told my boss I was pregnant a few weeks ago. Until then he had ever told me there were any issues with my performance. Since then he has asked someone else to "help" with my responsibilities 1 day a week. He has also said its unlikely I can have my old role back even though I only want to take 26 weeks mat leave. I have also seen my role advertised as a permanent role on job sites (it was added after I told him I was pregnant).
Anyway, I don't know whether to make a complaint or not.

Are you in a trade union? If not then it would be a very good idea to join one.

Collect any and all evidence of what is happening - take a screenshot of that job ad, keep copies of emails, make a note of things said and the date. Did you tell them of your pregnancy in writing, e.g. in an email? If so then keep that email - save emails by forwarding them to your own private email address and/or printing them.

Hoping others will be along with more advice too...

Yeah I told my boss via email. I don't have a trade unions but will call ACAS, thank you. I do have a HR department but I'm worried about them making my life difficult before I leave (my hr contact is good friends with my boss, they worked together at another company) It's sounds naive but I never expected them to be like this, and I'm worried they will say I'm being paranoid. My company are always hiring back fill, but it's suspect that this job was advertised after I Told them and it's only for where I'm based..(normally they hire for a county or a region when they are back filling)
I have kept everything that I've seen too, thanks for your help

Your HR might be mates with your boss, but if they know anything about their subject, they will know that he is sailing close to the wind and will tell him, for his own benefit.