Question about very minor intrusive thoughts?

well, im turning 19 soon and i was just wondering if other people have similar days like this, someetimes on days where im feeling shitty, i love my girlfriend sooooo much but some days when im feeling shitty, i seem to get an intrusive thought out of nowhere like am i sure i still love her, or something like that, and it really bothers me, and then i work myself up in my head abut it and it will bother me on and off for maybe that day or so, but on the days i feel great i know i love her so much, im basically just wondering if minor intrusive thoughts like this are really unnormal for people, because i never used to get aeven a doubt like that, this can be related to other things, like maybe when i got depressed i could think like, what if im gay, and then almost convince myself i am, even though i 100% know im not gay, never in my life been turned on by a guy, i basically feel like sometimes i get thoughts that i know arent true, but seem to convince my head towards the negative side, until i get really upset, then boom, its like i fealt like an idiot and my head is clear of this ****, im almost thinking its just related to days i could feel a bit depressed, i dont really know where im going with this, please comment