Question regarding placeing all in bet in home game.

[SSSAce]

5 of all were playing $0.25 / $0.50 NL Texas Hold'em tonight. We are all friends. I am the most experienced player of the bunch. A couple of the guys talk about hands a bit, drink too much, preasure people to call; the standard home game stuff. Tonight we all bought in for 30. One hand was a bit weird. I was on button with A 4 offsuit so I raised it to 2 bucks. I flopped the top two pair. Ac 4d 3h was the flop. 3 callers so I slow played a bit and checked. Double Check. The turn came 5c. I bet out 5 and got called. River was a 10c. I bet out 8 and got re raised for 25. I thought he might have A 10 or the flush or staight. I still had the two pair. It did not add up so I went to call. I said oh f*** and went to drop my chips toward the middle of the table. Just before I let go of the chips my buddy pumped his arm in the air in celebration. Instintivly I did not drop my chips. My other buddies said I had to call as I said 'all in'. I did not say it and I did not drop my chips. They wanted me to call bad as they wanted to see the hands. They said I had to call. I felt like I did not have to call as I was given the information that I had a losing hand. I then looked at my opponent and alomost called again. I was thinking a couple of mins. I looked at his face and almost called. He celebrated my almost orriginal call so I thought he had the a 10 or flush. He is not the best player so I thought he might just have middle pair only. Finally I did not call. My friends would not let it go and said I should have been forced to call. My one friend keep on me later and I told him I was a little insulted that he thought I was lyeing about what I had said when I almost called. Talking to the pot winner later, he did have middle pair so I would have won the hand.
Question, do the rules say I have to call? I would rather call the 25 rather than have everynone pissed at me for not playing correctly. Thanks in advance.