Could I be pregnant whilst on the pill?

So I came off the mini pill a few weeks ago since i started antidepressants (citalopram) and I thought the pill could have been contributing to my low mood. I don't get periods whilst on the pill and I didn't get any in the few weeks I stopped taking it, although the I had a few symptoms that made me feel like I was about to have a period (PMS).Two weeks ago I had sex for the first time with my new boyfriend however i had only started back on the pill 7hrs earlier. I had a small panic the day after but since I haven't been having periods felt it probably wasn't possible that I was pregnant (I was 15 last time I had a period and I am now 18). Recently I've been feeling bloated, have had a few strange pains in my lower tummy and had the munchies but these could he symptoms of being on the pill. Sometimes I feel sick in the morning but I haven't been sick but this may be a symptom of the anti depressants. Really confused and the Internet isn't very helpful. My mum got pregnant on the mini pill with my brother 15 years ago which is a bit concerning 😅 What does everyone think? Is it worth taking a test? I don't want to buy one if there's no possible way I could be pregnant since I have no job and not much money. Thanks in advance for any advice given 😊