Vivica2, Sorry things are so confusing right now. Aren't we wonderfully mysterious creatures!
I had 5 days of pos OPKs during my second cycle (I think, or was it third) after my m/c earlier this year. I too was very weirded out because I'd always had very regular cycles. As far as I know, and I'm no expert, pos OPKs just tell you that LH is surging, which it does b4 O, but if you don't O, for whatever reason (like your PP cycles are just starting out or your cycles are trying to return to normal after another disruption) you can get multiple pos OPKs as your body attempts to O. (I did O that cycle, just a few days late.)
Wouldn't worry too much. Especially with DD2 still nursing a bit. My GYN told me that my cycles may not be totally normal until I was nursing less than every six hours on average. Night nursing can be especially disruptive. I only assume that these things are even more "disruptive" as we age and our natural fertility declines.
On the other hand maybe you are pregnant!
Unless that's a faulty pregnancy test (or there is something really strange going on, like the "hook effect"), you're not pregnant. OPKs are actually made to be less sensitive. You don't want your OPK to register as positive constantly so the sensitivity has to be at a level where it will only turn positive during a surge. Pregnancy tests want to measure as low as possible (within reason as an hCG level below 5 can be unrelated to pregnancy). Therefore, a First Response will turn positive before an OPK.
Cycles can be all whacked out when they first come back. Its the body's way of trying to balance the cost of the baby you already have with the benefits of having another. Breastfeeding can also cause short luteal phases, not giving the egg enough time to implant, as a late stage of the return to full fertility. Having a baby can also permanently alter your menstrual cycle. Some women find their cycle is longer or shorter, that they have cramps they didn't have before or don't have cramps that used to keep them home, and there's that occasional story of women who get pregnant with their 2nd completely by accident after spending years trying to conceive their first.
Personally I've found that odd LH surges can also be caused by PCOS. I had a 4+ day surge (I stopped testing after 4 days of positives) when I got pregnant with DS, except the surge didn't start until I was ovulating and continued on to/past 3 DPO!