Tooth extracted, still terrified of infection coming back

I had a broken molar for over a year (if not longer) that I (regretfully) ignored. It was halfway broken and I could see where it was turning dark inside. About two weekends ago, I suddenly had pain around that area of my mouth, the most intense pain radiating along my lower jaw, into the jaw joint and ear, and down the side of my neck. It got worse as the night went on. The pain would subside for a bit, then come back, especially if I lay down.
The next night I went to urgent care, and she told me she didn't think it was infection because the pain came and went, it wasn't constant. So she put me on pain relievers until I could get into the dentist. She did massage the gum where the broken tooth was, but that didn't have any effect.
Two days later I got into the dental clinic and they took x rays to see whether it was the broken tooth, or a tooth up top giving me problems. I saw the x rays myself and the broken molar had a big mass of black where the crown should have been. The x ray didnt show the bottom of the root, however. The dentist was certain it was that tooth that was causing me pain and offered to pull it that same day, but instead I opted to go on antibiotics for a few days before the extraction.
Penicillin VK was prescribed. Although the medicine made me tired, the pain was less constant and longer time between "bouts". I started taking them tuesday and didn't have an attack again until early sunday morning. THe next day I had the tooth pulled. I finished my course of Penicillin this past Friday morning. THe dentist was certain it was that tooth causing the problems, but I'm neurotic and am scared that the pain will come back. I saw the tooth after they pulled it (it was in a couple pieces, they had to cut it) there was definitely black in it, but the roots didnt look black or have anything on them. I have not had the terrible pain since, but I am scared that the infection will come back now that the antibiotics are done. Maybe they didn't get the right tooth, etc...

Anyone have any thoughts? It's been one week to the day since my extraction, and 3 days since I finished my round of anitbiotics. The only pain I have right now is in my jaw somewhat (more of a muscle ache) and from the tooth behind the extraction site, it just feels a bit irritated. Thank you for taking the time to read my post

I have experienced exactly the same scenario. The jaw ache you are enduring is just bruising caused by the original extraction and will fade away in another day or so

Thank you! That makes me feel a bit better. I just get nervous when I get little aches here and there, especially in my jaw joint.