On the pill: Could be PREGNANT??

Okay I need advice. I've been on the pill since the end of last year. And sometimes here and there I take it really late. Only a few times I've missed. But a month and a bit ago I was pretty slack with it, and I had a lot of sex without a condom around that time. Now I've been having my normal bleeding that I should around the time I should. I've also read that some people on the pill don't even notice they're pregnant until they see it physically. But only within the last month I have had so many symptoms that could relate to me being pregnant that I have never had before. I'm gaining weight, craving, feeling bloated, cramping, discomfort around the uterus, nausea, excessive tiredness and tender breasts, all throughout the month. I had taken an over the counter pregnancy test quite a few weeks ago, but nothing. But I haven't had luck with those tests and they haven't shown a hint. Any advice?? Things I should look for?? Any particular tests that are really good and easy to use?? Or is it just a phase?? What should I do??