Should i trust him with what he said?

last night he was at a party and he seemed wierd like overly nice and just rambled on about pointless things when i called him to say goodnight...im not sure if it was because he felt bad for not hanging out with me or if he was guilty of something else...or because he was drinking...today he called in the morning to say goodmorning...then i see a picture of him and another girl on facebook...and i just had that gut feeling so i asked him about it and hes like...yes i took a picture with her...and then i said sorry im just a little worried you seemed a little wierd last night then he called and said "are you alright" and i said "yeah" and he said "i wouldn't do that to you i don't want you to worry" and the i sad "okay..." and they he said "lacey, i love you" and then i said it back......is that beleivable? i mean that he acually called me to say it and he wasn't angry? orrr should i still be worried because he wasn't angry..and he was really like nice....god im so paranoid