[NSFW] Can anyone in the kink community help with a scene problem?

My husband and I are new to BDSM and have been experimenting a lot in the last few months. Last night after he got his thing done he was pushing for me to finish (which hasn’t happened yet). I was enjoying what was happening until I felt a pressure build up and got scared. I used the safe word yellow to let him know I was reaching a close limit. He gave me a break and started I’m again but a bit more intense. Quickly I could no longer handle it and I said the stop word red. He immediately stopped and I felt defeated. He got up to go to the hall for a towel and as soon as he hit the door frame I was sobbing. I don’t understand why I cried or felt so depressed, he was barely gone a minute. He came right back to me and went into aftercare which lasted a good hour. Did something happen wrong, am I being ridiculous, or how do we help this in the future? I have never cried before.