OP I feel for you, I had the same when DD was tiny , my parents then the in laws came to stay when DD was a week or two old - we had no choice at the time but never again. I was better off as they would (well, the women at least) do jobs to help, although MIL boil washed everything and shrunk all my clothes - I hd a C sect though, so they really had to, but my god they did my head in. I actually became unhinged just having them there.
Why not ask them to take baby out for a walk, so you can sleep or shower? Although mine did that and I hated every minute when she was gone. Surely they cant be thick skinned, if you said 'it would be brilliant if I just had someone to help with washing up/hoovering/washing whilst I sleep/feed baby/shower/dress/eat chocolate...
Just tell them - honestly, they might have gone away or be being distant because they don't want to step on your toes, or get involved if you don't want them to, or maybe they just feel unsure around a little baby? My MIL does, she just had no idea what to do, felt like she would break her I think. Mind you, she isn't much better now with a toddler...
Honestly is best, if you are a bitch to them then just blame it on hormones or tiredness, it really is important you sort it out though, as trust me the situation won't get better on it's own...