From pills to the shot

I am currently on the pill but it is really hard for me to take them because if I don’t see a change in myself from it I just don’t take it. I recently talked to my dad about getting it changed and he said he would talk to his girlfriend about what would be best (she is a nurse) and she said the Deposhot. I did some research and it said that it should stop your period for those 3 months. That is terrifying to me, my boyfriend and I do some sexual things and have sex once in a while(protected) so not having my period for that long is terrifying to me. Is there any other way than pregnancy tests to sooth my stress? I get the stress of being pregnant even when I haven’t had sex since my last period.