Manige,
I'll give you a little more support as I was recently in your shoes (and BTW, your daughter is NOT too young...mine is the same age as your kiddo and it has been great other than errors on MY part)!
First, do not give up! I know it's messy sometimes, but you really do not want to have to start completely over, do you? We kept going through our move and my son regressed to having just one accident or so a day for a couple of days and he was back to normal (regression does happen but it does not have to be long)...it depends on how big of a deal you make to her about the move (or new baby or new change) that really makes a difference. Also, remember that at this age, we are truly just training ourselves to take them (but they are smart and get it pretty quickly too) so I find that if I am going to be out of the house or have a busy day, I set the timer on the stove or on my cell phone to remind myself to ask my son if he has to go and to take him potty...works pretty well! (Plastic training pants also work well for those "in the car" times if pull-ups don't work.)
And on the topic of putting them back in pull-ups (or diapers), I have experience with that too! First, my 6-month-old niece came up to visit and shortly after she left, my son brought a pull-up to me (we call them night-night underware and he was wearing them occasionally at night when he had diarrhea...stomach issues, yuck!)and said "diaper"...ugh! So, anyway, he got really sick for several weeks and had diarrhea all the time (to the point that I had to throw away 4 pairs of underware in an hour) so I made the decision to put him in the pull-ups to "save" money...which he still called diapers thanks to my niece's visit...and now that he is better (and I had a baby so I was willing to be lazy at the time), we are almost having to start with square one AGAIN! He got lazy and I got lazy and we went from having no accidents a day to now having several (we are back to only 1-2 a day when I remember to take him all day long)! Not good...so I would avoid the tempation to put her in diapers/pull-ups again with every bone in my body! Despite it being messy at times, it will be worth it in the end (you might also want to put LOTS of plastic shopping bags in the car for wet/poopy clothes and make sure you have a bag packed with extra pants and underware for the trip and maybe buy a cheap plastic potty to put in the car for those long stretches where potties are unavailable (or disgusting)...). My son used to go poopy in the potty (when he had diarrhea, he could feel it coming so he'd tell me), but now that the diarrhea is over, I am having the typical pooping problems that all the other moms have...yuck...but I just watch for that "serious" look (or him hiding or passing gas) and grab him and put him on the potty!
Ultimately, keep up with it! She will get it and have an a-ha moment (it takes a bit for that- think my son took a few months or so originally-, but it's worth it when it comes- but like I said above, we start out by training ourselves- I can tell you that my son, even now, takes little to no time to pee on the potty when it used to take him 30-40 minutes to get pee to come out- he now pees on demand and tells me he has to go sometimes!!!) and she will start telling you more consistently, but don't give up!
S., mom of 22-month-old and 5 week old.