Worrying I can't have children 😔

Me and my partner have known each other 15 years but only been together 3 years being friends before we got with each other and knowing each other's past really helped us with any trust issues we used to have in other relationships we really are the best of friends he's 24 and I'm 21 and I know how much we really would love to have a baby and I couldn't think of anyone better then him he's got 23 nieces and nephews and he's an amazing uncle And now it's his turn to be an amazing father, we have been trying for a baby for the past year now he's been to the doctors and his sperm count is avarage which now has me worrying if it's me, my periods are all over the place, I can go two-three months without coming on my period then the next month I can come on heavy for 7days or maybe a little spotting for two days, he's been asking me to go to the doctors but I don't think I'm strong enough to hear I can't have children just yet so I'm a little scared and bury my head in the sand! I was on the injection and came of that about 4 year ago x