I'm paranoid that I might be pregnant?

So I had sex about 48 hours ago now. It was my first time, and he used a condom the first time he penetrated me. I know it didn't break, as I checked it myself, but I'm worried because I didn't know about the possibility of leakage/spillage when pulling out until reading online so I didn't pay attention to that. Since I threw the condom away myself, I noticed that it was relatively dry (not a lot of semen). After the first penetration, we proceeded again with a condom, which also did not break. What I'm paranoid about is that we fooled around for a bit after, and his penis did enter me slightly. Because I'm so paranoid, I've convinced myself that I have pregnancy symptoms (headaches, bloating, urination). Is it possible to have symptoms this early? What is the likelihood that I'm pregnant? Plan B is expensive (I'm a student) and if there is not a large chance that I'm pregnant, is it worth it to put such a high dosage of hormones into my body? Should I take the Plan B pill?