It could be a possibility. I reckon it's best to just get a pregnancy test kit and find out once and for all. Have you experienced any other symptoms that pointed to pregnancy, symptoms that you had during your first pregnancy? A friend of mine found out that she was pregnant a little after giving birth because her boobs felt super sore (sorer than usual) while she was pumping milk.
If the usual name brand test kits are too expensive, you can consider getting the ones from the Watsons brand. Costs $7.70 per kit.
http://www.watsons.com.sg/Product-Categories/Health/Family-planning/Pregnancy-Test-Kits/One-Step-Pregnancy-Test/p/BP_72303
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