Is Pregnancy Possible If Intercourse Was On The Day Of Menstruation?

I had sex about a month ago with my boyfriend for the first time and we didn t have any condoms and were a little scared to buy some, so we used a grocery bag. I don t know if he ejaculated inside or not, but when we were doing it, apparently I just started my period. Every sense then I ve been feeling scared that I could be pregnant. So far, I feel bloated, but that could be anything. I suddenly felt overwhelming gas today. My breasts aren t swollen and I don t feel dizzy, but my brain is pulsing. That could be from my lack of antidepressants... I m scared I might be pregnant. My period stopped about a week or two ago and I m a little scared even now but I keep telling myself I couldn t have gotten pregnant by then. I m 15, and I don t want my parents to find out I had sex or am possibly pregnant. If I get an abortion, or an abortion pill, I don t want to have them find out and I don t have any money to pay for it... Is there any alternatives?