Help me please

I'm not sure what wrong with me no pierod of yet been a week or more (tmi) sorry been very gassy my stomach feel weird I'm not if it because of gas but I just don't feel the same at all the day I miss my ad I took a test and it was negative and a couple day later I had what I thought was my pms but it lasted a day and it was very dark like brown I need help I'm not sure what wrong and n y doctor office is very far and if any can give some idea on what it could be this might not all make sense I'm sorry I'm nervous