Interviewing for jobs then discovered I'm pregnant

[CarrieDS]

I have two small children, and have had a part-time job for the last 2 years since my kids were born. Unfortunately that came to an end recently, and I am job hunting for freelance work, or possibly a part-time permanent role. In the last few days some fantastic opportunities have come up, and my diary is filling-up with interviews and meetings; some roles through people I worked with before pre-kids, and some new people and companies through recruitment/ headhunters. However... yesterday I discovered I am accidentally 3 weeks pregnant.
I really don't know what to do and feel really down about it. It's hard enough going back to work with small kids, and interviewing etc. without also knowing I am pregnant.
We always thought we would have a 3rd baby, but this has happened at a time which is just when we need some £ and I was making great leads in the job hunt. It will also put huge strain on our family, it's already hard with 2 small kids.
I know I should think about myself & baby first, but I feel like one way or the other I will only end up letting people down...
Would you think it would be okay to take a freelance role ie. 4-6 months contract knowing I am pregnant? This is all I would need to tie us over financially, and I felt very well in my other 2 pregnancies so I should be able to work fine. It's not like they would need to pay me anything once I am off to have a baby. I just... and I know this is ridiculous... feel as though when they find out, it's going to be awkward (let's face it, people will immediately think I will be going to hospital appointments etc. which may sometimes be the case) I suppose it depends on the company, and maybe I should look for one I feel will be supportive/ won't matter. I know they can't discriminate, but we all know the reality and i don't want to work somewhere where I feel unwelcome.
A lot of these roles are to be permanent, and I don't feel I can go for a permanent role - looking them in the eye talking about our future together! - knowing I will then have to tell them I am pregnant. My husband thought I should... but he isn't the one who will have to go through this!
At the moment I am just going to go for all interviews over next week, see what they are like, see how I feel after (and if I get any offers) and then make a decision but I am mega stressed and upset about it all.
I'm even considering a termination which I feel guilty that I am thinking about it.
On top of this we are going on holiday with friends in a couple of weeks. I had been so much looking forward to it, but now I just feel like there will be a black cloud hanging over me. I don't really want to tell anyone, unless I am 100% sure I'm keeping the baby.
Very stressed and down about this situation.