I am still feeling the pregnancy symptoms but also feeling slight cramps in my stomach

Over 6 weeks ago i had sex with a partner about 4 or 5 time during my period and we used a condom on 2 occasion but the other times he pulled out before coming. The next period i had was 3 days late and started with stomach cramps before i even started bleeding and i only lightly bled for about 3 days which wasnt normal for me. I continued with my pill when i finished my period and the a week later i had sex with my partner over the weekend and he came inside me at least 3 times but i was on the pill but consumed a lot of alcohol that weekend. then a week later i started to feel a bit nauseous but it got worse and worse and then i started to get headaches and feeling dizzy. Even on a few ocassion i thought i was gonna throw up. now my period is 4 days late but this morning i started to get a brown colouring when i went to go to the toilet. I am still feeling the pregnancy symptoms but also feeling slight cramps in my stomach. Can anyone give me some advice, i would really appreciate it cause i have no idea whats going on anymore. Thank you