My hormones are all over the place

So last month I just started a new pill cuz my previous one was causing breakthrough bleeding. So I didn’t have sex the entire month until the day right before my period since I knew I wouldn’t be ovulating. Yes we used a condom and he pulled out way before finishing. Then the next day I got my period and it lasted a full 5 days. So that means I’m definitely not pregnant right? Well, now I’m on my second pack of pills and I had to take antibiotics this month which lowers the effectiveness so I haven’t had sex and my boobs have been sore and I’ve had brownish(old blood) mixed discharge twice within the past week. My period is due in 6 days. There is no chance of pregnancy right? Is this just cuz my body is still adjusting to the new pill? I take Tri-Lo-Sprintec btw