I think the girl I'm seeing is becoming distant over a missunderstading that happend on Thursday please help?

Well it started on Thursday I went to pick her from work and she didn't know I was coming and really I should have text her I didn't I saw her walking up to the road and I just pulled on to the curb and waited and I noticed she got into a black car with her work mate they drove past me slowly they went to stop then they just sped off up the road I followed and she went into a shop she came back out and I picker her up thee and then and drove to her place. So after and hour and half off cuddling and kissing she asked me why o went to pick her up (it was cold and wet) and she said "ya should off text me oh well gives me something to tell me me work mates tomoz about ya" I said "don't i will be a laughing stock" she kept going on and on joking about it and I said in seroious joking way "see ya tomoz bye" she pulled a face and said I was being arsey with her and I wasn't then she said "I don't know how to act around ya no more" I'm puzzled I just said " do ya want me to come down tomorrow she said up to u so I just left and said "ok i will pick you up and cook dinner " and then I just went home.so last night I picked her up and cooked dinner before the dinner we hardly spoke thow she knackered from her long shifts after dinner we talked for abut and watched a film I hold her for a bit or I tried to lol but she did say "sorry I'm been a bit boring" I just said it's ok. Anyways I said "I will pop down on Monday at about six if ya up" she said "I should be I think" I gave her a kiss and went home and I did apologise To her just saying I didn't mean to offend you or anything she just said "it's ok". So that was that but I just feel like since that happened on Thursday I'm gonna lose her her this is my FIRST PROPER relationship so I'm am inexperienced on how to handle situations like this it's been nearly 2 months since I started seeing her and she wanted to take it slow when I asked her 2 weeks a go am I worrying over nothing what's your point on this cheers guys