Thank you for being so nice everyone, you just made me cry a little 
I may have briefly told you (I honestly can't remember) so I'm sorry for the mammoth post in advance...
So as you know we got married in partial secrecy on New Year's Eve. A week later when I was only 5 weeks we told DH's brother and his wife (his wife was mopping at the time) and not once did they congratulate us, SIL did not even stop mopping. She quickly them told me that DH's other brother and his girlfriend could not have children and that this news would kill her. SIL then proceeded to tell me all evening how children had ruined her life to the point where I started to cry and went to bed. She kind of apologised the next day but has still not been particularly excited by our news since (even after our early scan) and has really upset me as we are so close usually.
Anyhow, when we told DH's mum and dad I spoke to MIL and said I'd like SIL (who can't have children) to know earlier than everyone else so she has some time to get her head around it before everyone started talking about it. She agreed. So DH and I told his brother and asked him how was best to tell his girlfriend and he said it would be better coming from him. He told her, and apparently she was fine. I was continually made to feel guilty about my pregnancy with both the nasty SIL and my MIL making comments about 'poor SIL' she will never experience this etc etc and that they were both DREADING the next baby to come along in the family. They also think we only got married because I was pregnant.
So I spoke to MIL after weeks of worrying about my poor SIL and how she was coping with the news and said I would like to see her. MIL said she would ring her to make sure me turning up at her door would not upset her. MIL told her on the phone that I was desperate to see her and show her my scan pictures and share my news with her - HUGE LIE. I am not insensitive. I feel like I've not been able to enjoy this pregnancy because of this guilt hanging over me. SIL rang her boyfriend in floods of tears saying I was just going to turn up and shove scan pictures in her face and basically remind her about what she won't have. DH's brother rang me, I explained that was not the case and apologised. He said he would smooth things over.
I then contacted nice SIL myself about meeting up this week during half term. She said she would love to. So today I went to meet her- first words out of her mouth were 'I haven't seen you to congratulate you!! I'm so thrilled, tell me everything'. She was so excited. So I told her short version without adding any details that may upset her. I then said that if she ever wanted to talk that I'm here for her, or if she needed company at any hospital appointments etc. She looked at me with a kind of blank face and said, 'what have you been told?' I told her both SIL and MIL told me she had gone through early menopause at age of 37 and only chance of her carrying a baby was egg donation - but cut off on nhs is 39, she's 38 in a few weeks, and waiting list is 12 months and by time her turn came around she would be 39 - too old to do it on nhs. She looked horrified and told me THAT WASNT TRUE. I nearly died on the spot. She said that it was a possibility that she had gone through menopause but after tests etc it was found that she was still ovulating and that although chances are reduced because of age and other factors it's not impossible. I couldn't believe it. MIL and SIL had actually lied to me. I felt sick. I just don't know what to do, what to say or why they would tell me that and put all that stress on me when I'm pregnant.
I'm so sorry for that essay but I feel Somuch better for telling you. I'm sobbing as I type but I think from relief because I can tell someone the whole bloody story xxx