I would just make sure that you stay hydrated. And hey if you can still walk 2 miles, I think that's wonderful! Ever since my son dropped, I can barely walk to the bathroom!
If your really concerned though I would discuss it with your doctor and make sure that she/he is okay with it, but walking is good for pregnancy, just don't get dehydrated or overheated!
Walking and exercise is really good for you if u feel you need to slow down or stop then do it but of u feel ok you go girl!
I walk everywhere I'm 36 weeks and iv just done 4 miles around the beach today
I'm 29+5 and I walk 2 miles a day since I was 19 weeks.