Are these signs of pregnancy???

Arial • I`m 26 years old I have 4 wonderful children 2 girls & 2 boys and 2 angel baby`s!! I`m engaged to a wonderful man!
So I had sex with my husband on October 17th and 19th I ovulated on the 19tb or something like that well this app said I was 33% chance of pregnancy on the 19th and for the past couple days my nipples have been hurting and I feel really bloated below my waist and today 10/23/15 I have been feeling super nauseous and my sense of smells has gone up. I have a feeling I am pregnant. But I just don't know if that makes any sense!! I knew I was pregnant when I was three weeks with my 1 year old went to the doctor and they confirmed! I was trying but then things in my relationship have not been going so well. But either way I would be happy if I am! Sorry I'm rambling on but my question is are these signs that I could be pregnant I don't know I just have a gut feeling that I am. I am a mother of 4 kids it's been almost 2 years since I was last pregnant. So all the advice is welcome TIA