I went off the pill about a month ago, and this morning I woke up with 3 cold sores that came up over night, could this be an early sign that I'm pregnant?

They aren't really a sign of pregnancy, although they can be more common in pregnancy because of the changes in hormone levels. This is the same reason why some women are more prone to having them around their monthly cycle.

You'd need to see what happens with your periods. They could be regular right after stopping the pill, or they could be a bit irregular for awhile. If you are trying to become pregnant, and you don't have a period, try a pregnancy test... perhaps one each month until you either start having periods again or you get a positive test result, whichever comes first.

Common early signs of possible pregnancy for most women will be extreme fatigue, nausea, frequent urination, feeling as though your period is about to start, more noticeable breast tenderness, and of course a lack of periods. When you might experience these, and which ones you may or may not have, will vary from person to person.

This is not normally a "early sign". As noted, some or even many women, have no early sign, and first discover when they miss a period. Most real signs start happening some weeks after the missed period.

While of course you can even get pregnant, while on the pill, it is doubtful that you would get pregnant in the first month after, and often can take months, even over a year for couples to conceive.

I went off the pill about a month ago, and this morning I woke up with 3 cold sores that came up over night, could this be an early sign that I'm pregnant?

No. Cold sores are signs of a oral herpes infection flaring up, not pregnancy. The best mostly conclusive symptom is that you're missing a period, and even then it has to be late for more then two weeks before you test for pregnant. Your periods can be a little odd for the next couple months while your body adjusts to the absences of your oral contraceptive.

Since I am assuming you're wanting to get pregnant, you're going to be watching and wondering about EVERY little thing that your body does from here on out and you're going to be seeing pregnancy symptoms EVERYWHERE. Your boobs are sore, period is late, mid-cycle spotting, cramps, cravings, and the list will go on. The problem is that most of those are easily explained by non-pregnancy reasons. IE PMS, hormones rebalancing, stomach flu, Bad Burritto, nutritional deficiency, and the like. I know it is easy to get your hopes up, but that will just lead to disappointment.