Hi red,
Firstly dont feel pressured to feel happy because you are pregnant, it may be that being pregnant is whats making you feel this way. Your body is experiencing a rush or hormones and changes that it can find hard to cope with.
May people hear about postnatal depression but antenatal depression is also quite common.
Firstly, speak your GP or midwife asap and explain your fears and concerns and how you are feeling, please make the effort to speak to them.
Most mums feel scared at the prospect of giving birth and coping, thats natural but it shouldnt make you feel so bad.
I have used the ivillage boards for almost 3 years now and have found lots of support for various things over the years. I had no experience of depression but heres a link to their antenatal depression board. Im sure someone there will be able to offer advice as well.
http://messageboards.ivillage.co.uk/iv-ukpbcwa nd
Good luck and best wishes for your pregnancy.