Pregnant and engaged...need advice

Ok, so I'm due in March 2018 and we decided to get married in October. We decided together that we would do this because we knew it's what we wanted and we had planned on it at some point but didn't get engaged or anything.

my questions:

1) I don't have an engagement ring. I would like one, but don't want to spend any extra money on that versus the wedding and baby. What's a good way to improvise until I can get a real ring? Should I get a decent fake ring until then?

2) if people ask about my engagement, what should I say? It isn't very romantic as we agreed on this together. To us it is, but it was a more laid back kind of thing rather than some grand gesture...

3) where is a good place to look for a wedding dress that would fit my baby bump? I'd be around 20 weeks on day of wedding.

Please no judgement 😊