I'm Not Sure How Far Along I Am And I

I'm not sure how far along I am and I have an appointment tomorrow with my obgyn but I'd like to know now. I believe my last period was about 4 months ago at most but with how much I'm showing I feel that I may be having twins. I went to bed feeling very sore all over my body like every move was felt through every muscle. I woke up today and felt even worse now with a huge headache and feeling extremely weak and feeling cold. My temperature was only 98.3 should I be worried?